Calculated signed sum

Algebra Level 1

x + y = 55 x y = 27 \large x + y = 55 \\ \large x - y = 27

If x x and y y satisfy the equations above, find the value of the larger variable.

51 31 41 43

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132 solutions

Victor Loh
Jul 22, 2014

We can use elimination to solve this system of equations.

x + y = 55 x y = 27 x+y=55 \\ x-y=27

Adding these equations gives:

2 x = 82 x = 41 2x=82\implies x=\boxed{41}

x + y = 55 ( 1 ) x + y = 55 \cdots (1) x y = 27 ( 2 ) x - y = 27 \cdots (2)

From ( 1 ) (1) ,

y = 55 x ( 3 ) y = 55 - x \cdots (3)

Substituting ( 3 ) (3) into ( 2 ) (2) ,

x 55 + x = 27 x - 55 + x = 27 2 x 55 = 27 2x - 55 = 27 2 x = 82 2x = 82 x = 41 x = \boxed{41}

Farah Azwani - 6 years, 10 months ago

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You had Y=55-X but you substituted it as 55+X why is that???

Ahmad Albadry - 5 years, 10 months ago

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substitution of equation 3 in equation 2 ... eq 2 x - ( y ) = 27 ... [eq 3 says ... y = 55 - x ] => x - (55 - x ) = 27 ..... => x - 55 + x = 27

Bhanu Rekha - 5 years, 9 months ago

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@Bhanu Rekha or simply... (x+y=55 plus x-y=27 gives us 2x = 82 therefore x = 41... obviously by second equation it is understood that x is greater than y so, the answer is 41

Bhanu Rekha - 5 years, 9 months ago

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@Bhanu Rekha This was how I solved it, but only after I figured out what they were asking. The wording was also a challenge, but I am not sure it was intentionally mis-worded. Either way, my grammar geek, word nerd self was in crisis until my math self won out by telling me "Who cares? Answer with the value of x - otherwise equation 2 would be negative." And I did! My multiple personalities can be a problem...

Neill Conroy - 5 years, 9 months ago

He distributed the -

Laura LaMie - 5 years, 7 months ago

(x + y = 55)

(x - y = 27)

        2y=28
          y=14
tadaaa if y = 14 and we know that x + y =55 (substitute) x + (14) =55 x = 41

tadaaaa

Jao Garcia - 6 years, 10 months ago

X+y=55

X -y=27

2x+0y=82 2×=82 ×=82÷2 ×=41

Mariah Mariano - 5 years, 11 months ago

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Liked your method

Ernesto D. - 5 years, 10 months ago

I have never seen this method but i really like it

Breanna Tysinger - 5 years, 11 months ago

I swear it should be same sign subtract so 2x is 28? And 2y is 82??

Ollie Baker - 5 years, 1 month ago

Personally, I was utterly confused by this question.

David Harrison - 5 years, 2 months ago

Wording deceiving

Kathy Boyer-Shick - 5 years, 1 month ago

Problem was poorly worded. But keep on posting!

Brandan Ticas - 5 years ago

In this solution, it was not shown that 41 41 is the larger number.

A Former Brilliant Member - 3 years, 10 months ago

If I set x or y = 0. Then the larger number is. 55. What kind of solution is that.

Mark Taay - 5 years, 10 months ago

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55-0 isnt 27 my friend

Curro Romero - 5 years, 2 months ago

How do you figure that? Yes 55+0=55 but 55-0 does not equal 27 so that does not work.

Michael DiVittorio - 5 years, 10 months ago
Nemo Maximus
Jul 22, 2014

Take the first equation and rearrange making y as the subject

x + y =55

55 - x = y

Substitute in equation. 2

x - (55 - x) = 27

2x = 27 + 55

x = 82 2 \frac{82}{2}

x = 41 \boxed{41}

Thanks, I get it now. It's been a while 😊

Dalmien Pichardo - 5 years, 1 month ago

I like it when the working out is explained this way. Thanks so much 👌

Andrea Rivero - 4 years, 11 months ago

I maybe really dumb, but why have you calculated the value of x alone? Why not y?

Babdu Lwasa - 4 years, 8 months ago

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Well look at "x-y=27". This translates to, "the distance between x and y is 27." This should remind you of the definition of absolute values. Consider x<y and x>y. The first one is impossible because you can't get +27 by subtracting a bigger number from a smaller one. Therefore, it must be true that x>y. The question asked to find the largest value of one of the variables. Since x is the largest in the set (x,y), the goal is to find the largest x value that satisfies the given conditions, and this would be the answer. Hopefully I've made sense.

Mike Pepen - 4 years, 8 months ago

This solution is longer. Elimination method is faster looking at the given equations alone.

A Former Brilliant Member - 3 years, 10 months ago
Joshua Ong
Jul 21, 2014

x + y + x y = 55 + 27 = 82 = 2 x x+y+x-y=55+27=82=2x thus x = 82 2 = 41 x=\frac{82}{2}=\boxed{41} .

Beautifully solved! Congratulations, Joshua.

Eury Luna-filho - 5 years, 10 months ago

Not a good explanation

Juan R Rodriguez - 4 years, 11 months ago
Jay Prescott
Jun 21, 2015

55-27=28 Half of 28 =14 27+14 = 41

Exactly what I did.... Easiest way of working it out haha the amount of thought that others put into this is ridiculous 😂

Riley Cross - 5 years, 11 months ago
Hari Eeshwar
Jul 28, 2014

As we know, Max{x,y}=(|x+y|/2)+(|x-y|/2) Hence, Max{x,y}=(55+27)/2=41

Is it really possible?

Rajdip Mahat - 6 years, 9 months ago

explain this please?

Ankit Vijay - 6 years, 10 months ago

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Apply properties of absolute value, if 0 < x < y 0 < x < y , then x + y = x + y | x+ y | = x + y and x y = y x |x - y| = y - x , simplify, you get your answer. Or 0 < x = y 0 < x = y , then x + y = x + y | x + y | = x + y and x y = 0 |x-y| = 0 . Or 0 < y < x 0 < y < x , then x + y = x + y |x + y| = x + y and x y = x y |x- y| = x - y . Either way, without finding the values of x , y x,y , we can find the maximum of x , y x,y .

Pi Han Goh - 6 years, 2 months ago

You really make this easy question become harder.

Mokey Mokie - 5 years, 11 months ago

This is probably sentensially correct, using logic, and my fourth self that writes code would have done it that way, because it would use the least amount of code and would be useful in more difficult situations.

Neill Conroy - 5 years, 9 months ago
Zandra Vinegar Staff
Aug 5, 2015

In this problem, x 's role in both equations is the same, and y 's role "swings" from negative to positive. First adding y and then subtracting y is like watching a swinging pendulum with its pivot at x on a number line. The pendulum swings from 27 to 55.

Thinking about the problem this way, you can see that the distance 55 - 27 = 28 would be twice the length of the y pendulum. Therefore, y=14 . And therefore x = 27 + y = 41

Upvoted!!!

Abdur Rehman Zahid - 5 years, 7 months ago
Richard Clements
Jun 16, 2015

If X+Y = 55 and X-Y = 27, then 55-27 = 14 or 2Y

So.. Y=14

Then.. 55-14 = 41

A L
Jun 15, 2015

If x - y = 27, than x is 27 more than y. So x is larger, and y is smaller. However, now we have to calculate the actual numbers, we have 55 = x(27 + z) + y(z). So, 55 = 27 + z + z. Now, we simplify : 55 = 27 + 2z. 55 -27 = 2z. 28 = 2z. 14 = z. So, we go back, and we get 55 = x(27 + 14) + y(14). So, x is 41, and y is 14.

Snehal Shokeen
Jul 12, 2015

x + y =55 x - y =27

add +y and -y and the x

x + y =55 the y's cancel out

+x - y =27

2x =82 x=41 TADA!!!!!!

Shawn Pereira
Jun 29, 2015

x + y = 55 x + y = 55

+ ( x y = 27 ) + ( x - y = 27)

= > ( x + x ) + ( y y ) = ( 55 + 27 ) => (x + x) + (y-y) = (55 + 27)

= > 2 x = 82 => 2x = 82

= > x = 41 => x = 41 (Dividing both sides by 2)

x+y=55 . . . . . (1)

x-y=27 . . . . . . (2)

adding (1) and (2) we get,

2x=82

x=41

substituting x=41 in (1) we get,

41+y=55

y=14

therefore,x is greater than y.

Answer is 41

Durlab Das
Jun 24, 2015

Given that, X+y=55.....(1) X-y=27...... (2) Add equation 1 and 2 2x=82 X=41. Again, subtraction between equation 1 and 2 2y=28 Y=14.. We are compare between X and Y ...., X=41 ..is the largest numbers

Ram Dev
Jun 17, 2015

x+y=55 -------(1) x-y=27 -------(2)

add (1) & (2)----- 2x=82;

then x=41. Substitute the value of 'x' in any of the two equations.

From (1) we get 41+y=55 =>y=55-41 =>y=14

So 'x' is larger. X=41.

Mohammad Khaza
Jul 20, 2017

here it is , x + y x+y = 55 55 .....................(1)

and, x y x -y = 27 27 .......................(2)

adding these 2 equations, we get , 2x =82

or, x= 41....................[the larger value]

Moeka Hanzawa
May 30, 2017

(x+y=55) +(x-y=27) 2x=82 x=41

Waleed El-Geresy
Jul 3, 2016

Simply see that y is a number that if added to x gives 55 and if subtracted from x gives 27. We know therefore x is halfway between 27 and 55. We also know x is larger than y because x-y is positive.

Laura Beery
Jul 4, 2015

Write a solution. Plugging in each of the solutions, the only true answer was 41.

Sabika Ali
Jun 29, 2015

Find out any 1's variable value put it in other equation ..then choose the greater one..

Danielle D
Jun 28, 2015
  1. X + Y = 55
  2. X - Y = 27
  3. 55 - 27 = 14 so
  4. Y = 14 which means
  5. X = 41

55-27 is not 14

Karl O'Hara - 5 years, 11 months ago
Praveen Sharma
Jun 28, 2015

X+Y=55... (1) X-Y=27....(2) (1)+(2).. 2X=82 X=41

Ma Pm
Jun 22, 2015

(x+y=55) +

(x-y=27)

2x=82

X=82/2

X=41

Riley Cross
Jun 21, 2015

Work out the difference between 55 and 27 = 28

Devide by 2 = 14

Then either add 14 to 27 = 41

Or take 14 from 55 = 41

Grace Tobin
Jun 18, 2015

All I did was test each one

x + y = 55

x - y = 27

x = 55 - y

x = 27 + y

(x=55-y) - (x=27+y) = (28 - 2y = 0)

2y = 28

y = 14

x = 27 + y

x = 27 + 14 = 41

x = 41 y = 14

x>y

Rachel Stein
Jun 15, 2015

x + y = 55 y = 55 - x

x - y = 27 x - (55 - x) = 27 x - 55 + x = 27 2x = 82 x = 41

y = 55 - 41 y = 14

Can you explain this more detailed?

Shreya Patel - 5 years, 12 months ago
Qi Zhao
Jun 14, 2015

x+y= 55 x=55-y x-y=27 x=27+y

since x=x

55-y=27+y solve for y y=14

x=55-y=55-14=41 x=27+y=27+14= 41

Shreya Sinha
Nov 19, 2017

Adding both the equations we get 2x=82;thus x=41

Adding the two equations, we get 2 x = 82 2x=82 or x = 41 x=41 . Substitute x = 41 x=41 to any of the given equations to get y = 14 y=14 .

a n s w e r = 41 \color{#D61F06}\large \boxed{answer=41}

M Syafiq Iskandar
Jan 15, 2017

I actually do not understand with what you meant with : ...,find the larger of... What do you mean with the word "larger" in your question actually? Are you asking which value between x or y is larger? Thank you.

Marcos Brasil
Dec 28, 2016

Just add both of the sums then average to find the answer 55 + 27 = 82 82/2 = 41

Adam Marsden
Dec 21, 2016

Find the difference between the two number values which is 28. Divide by two, 14 subtract from or add to the number values = 41

Jay Dillon
Dec 11, 2016

3/4 + 1/4 = 1 3/4 - 1/4 = 1/2 Adjust proportions as above... the answer is halfway between the two values!

Emily Harrison
Dec 11, 2016

Imagine x is your base. That means x is directly in between 55 and 27 because you are only changing x's value by y. The difference between 55 and 27 is 28. From here either count down 14 from 55 or count up 14 from 27. The answer is 41.

Naga Raj
Dec 10, 2016

Add both equations We the equilibrium equation as 2x=82.From this x=41 Substitute x value in first or second equation, We get y=14

Leo Beattie
Nov 12, 2016

Subtract them from each other and 2y equals 30

Peter Morgan
Oct 12, 2016

Or, just find the mid point between 55 and 27. 55-27=28, 28/2=14, 27+14=41. Only works with this problem because Y is being added in one and subtracted in the second. Bit more problem solving route then algebra :)

Dan Cummings
Oct 8, 2016

x = 27 + y 27 + y + y = 55 27 + 2y = 55 2y = 28 y = 14 x + 14 = 55 x = 41

John Turack
Oct 2, 2016

55-27=28 28/2=14 27+14=41 Check work 55-14=41 y=14 x=41

The greater is 41

This method is question-specific to solve the problem without writing, using simple math you can do in your head.

here, adding two equation we get

x-y = 27

(-)x+(-)y = (-) 55 multipling minus to equation 2nd

-2y= -28 y= 14 ,put this value of y in equation 1st

x-14= 27 x= 41

X= 41 Y = 14 in which greater is x's value so answer is 41...

Pizam Yoyi
Jul 20, 2016

X+Y=55

X-Y=27

2X=82 X=41

Raakin Kabir
Jul 15, 2016

x + y = 55 x+y = 55 , x y = 27 x-y = 27

-You can also add the equations, but I chose to subtract the first equation from the second, in order to eliminate x x x + y = 55 x+y = 55 - x y = 27 x-y = 27 = 2 y 2y = 28 28 y y = 14 14 -I immediately knew then that x x had to be the variable with the larger value since 14 is less than half of 55. Now, all I had to do was to substitute the y y value into the first equation. So....

x + 14 = 55 x + 14 = 55 x = 55 14 x = 55 - 14 x = 41 x = 41

The final answer is 41.....

Shakaira Thorn
Jun 29, 2016

x+y=55 x-y=27

Subtract the bottom equation from the top to get: 2x= 28

Meaning: x=14

55-14=y

Y=41

Shree Ganesh
May 9, 2016

This problem is a mere beginner.

                x+y=55
                x -y=27

by adding both equations we get,

                2x=82

  so, x=41
        y=14

And, x>y

Finn C
Apr 11, 2016

First of all I found the difference between 55 and 27 (28).

Given that x was positive throughout the only difference between the equations was 2y.

Given this

2y=28

y=14

55-14=41

Moderator note:

Good approach to solving this system of equations by eliminating one variable.

Jason Shea
Mar 26, 2016

Since the same number is both added and subtracted from x, x must equal the number in the exact middle of the solutions. In other words, x is the average.

55 + 27 = 82

82 / 2 = 41

John Keegan
Mar 25, 2016

A long way of doing it, but requires less mathematical skills is substite each number in.

55-41=14, 14+27=41, therefore 41 will satisfy the equation. You can try these with the other three numbers and you will get; 55=31, 31=51 and 43=70

Haikalz Hafiz
Mar 23, 2016

I have solved it -with or without maths running in my head -I do not know how or why but it just seem that my thought process sometimes skipped steps and methods and led me to the answer . Unscientific , irrational , or people just would called it a hunch but I do took my time thinking about the number as well and of course if there were such steps and methods that I unconsciously used -it is probably by elimination.

Neil Henderson
Mar 21, 2016

55-27=28, 28/2=14, 27+14 or 55-14 =41. My maths doesn't go beyond Scottish Higher grade B, have i fluked this?

Grace Bismark
Mar 8, 2016

Using elimination we can get: 2x =82 ; x=41 while y=14 x then is larger equal to 41.

Equation 1st is:- x+y=55 Equation 2nd is:- x-y=27 Taking 2nd equation: - x-y=27 x=27+y Then; Putting the value of x in equation 1st.... 27+y+y=55 27+2y=55 2y=55-27 2y=28 y=28/2 y=14 Again;Putting the value of y in equation 1st....... x+14=55 x=55-14 x=41 This is required Answers: -.........41

Robert Allen
Feb 28, 2016

While the whole 2x = 82 =》x = 41 solution is more logical, I did something different to find both variables.

The addition and subtraction of y led me to understand that x is non negative so I found the difference between 55 and 27,

55 - 27 = 28

accounted for the number of times y was used in the equations (2) by dividing the difference by that number,

28/2 = 14

then substituted for y.

X + 14 = 55 =》x = 41, X - 14 = 27 =》x = 41

Tim Needham
Feb 20, 2016

Simultaneous equations m8 bare easy, rearrange to make X the subject then substitute into the other one

Andrew Hales
Jan 28, 2016

Look bros I did it on the first try. In my head. It goes somethin like dis: x = 41 and y = 14. So, yall gots it now. Easy peasy lemon sqweezy. Make dat lemon aid brah!I hope I helped simplfy this issue for anyone who had trouble.BRAH!

AND

Hà Nguyễn
Jan 10, 2016

You can do this: (55+27)/2=41 for the greater one

Otibhor Imuse
Dec 22, 2015

Using elimination method:2y=28....y=14 ....substitute into one of the two equations to find the value for x....using second equation x-y=27;x-14=27...x=27+14=41..x=41;so x is d larger number so the answer is 41

Hi Frit
Dec 3, 2015

Add the two equations, 2x=82 x=41 then 41+y=55 y=14 x is larger

DaLukas 101
Nov 12, 2015

x + y = 55 (1)

x - y =27 (2)

SUBTRACT (1) FROM (2)

2y = 28

y = 14

SUBSTITUTE y INTO (1)

x + 14 = 55

55 - 14 = 41 = x

Joseph Williams
Oct 23, 2015

I'm sure there was some formula or something for this, but I just used the fact that the numbers were related. I tried to simplify the problem by making the numbers smaller, so first I did: 3+2=5 and 3 - 2=1 where x=3 and y=2 So then I asked myself what is the relationship between the two answers, 5 and 1 I thought "well 5-1 is 4, and 4 divided by two gives me 2, the smaller number." Then I took this same question and scaled it up to the original. 55-27 is 28, and 28 divided by 2 is 14, which I assumed was the smaller number. Then I just subtracted 14 from 55 and got the larger number, which is 41

I'll probably have to go back and re-read the question, but if it was asking which variable was bigger, then that answer would have been x because if it was y, x-y would have been -27

BTW, I think I downvoted someone by accident while scrolling down on my phone, if it was you, just know it wasn't intentional :)

Navdeep Kaur
Oct 22, 2015

we have two statements
1) x+y = 55 2) x-y = 27

now take 2nd statement x-y=27 x=27+y

put the value of x in 1st statement (x+y=55)

27+y+y=55 27+2y=55 2y=55-27 2y=28 y=14

now for x value put value y in x=27+y x=27+14 x= 41

now we have x= 41 and y= 14 and x is greater

Robby Uy
Oct 19, 2015

(55+27)/2 = 41

Vaughn Fernandez
Oct 13, 2015

We need to solve both X and Y value to determine which has the larger value.

Since we have two unknowns we need two equation. (Eqn. 1 --> X + Y = 55) Eqn. 2 --> X - Y = 27

From Eqn. 1 X = 55 - Y ( Substitute this value to Eqn. 2)

Therefore, (55 - Y) - Y = 27 55 - 2Y = 27 55 - 27 = 2Y Y = 14

Thus the value of Y = 14. Substituting this value in equation X = 55 - Y,

X = 55 - 14 X = 41

Therefore the values are Y = 14 and X = 41

Clearly the X has the greater value which is equal to 41.

Muhammad Saim
Oct 13, 2015

Simply sum bot the answers and divid with 2 you'll get the answer

Hitesh Vijay
Oct 12, 2015

Solve these equations by substitution method

Pascal Meloche
Oct 11, 2015

x+y=55 x-y=27

55-27=28(=2y)

28/2=14(y)

X=55-14=27+14=41

Yolanda Lewis
Oct 11, 2015

X+Y =55, X=55-Y . 55-y- y=27 -2Y=-28. Y =14 (X-14)=27 X=41

Jake Marchington
Oct 9, 2015

x + y = 55

x - y = 27

55 - 27 = 2y, 2y = 28

y = 14 x = 55 - 14, x = 41

Sameer Padaka
Oct 1, 2015

Greatest number between x & y when both the values are unknown can be found using the below formula:

Let the greatest number between x and y be g. Then, g=((x+y)+|x-y|)/2

Brook Bray
Sep 30, 2015

(55-27)÷2=y=14 14+X=55 X=41

Andy Grond
Sep 29, 2015

55-27=2*y=28 so y=14 and 27=x-14 so 27+14=x=41 result: 41 > 14

Hany El-aziz
Sep 21, 2015

2x= 82 x= 41 y= 14

Dominic Parnell
Sep 16, 2015

x+y=55 => x=55-y. Therefore x-y=27 can be written as, 55-2y=27. So y=14. Hense x=55-15. QED the value for x is the larger where x=41.

Mubashir Baig
Sep 10, 2015

Named it first and second equation.. then take the value of x from equation 1..which is x=55-y

Now put it in 2nd equation instead of x..now solve it we get value of y which is 14 now put it in equation 1 and get the value of x..now tick the larger one..:)

Robert Sallette
Sep 10, 2015

55+27=82/2=41

Samôra Leninne
Sep 8, 2015

x + y = 55 / x - y = 27 dividing the system 2x = 82 we obtain, as x = 41, y = 55- 41 making we obtain y = 14, so the greater is 41

Luis Sioson
Sep 6, 2015

55 and 27 are equidistant to x, therefore, x must be their average, hence, 41.

Sopyan Thamrin
Sep 4, 2015

that was a comparison method...

and... this was a complete solution using comparison method :)

I think I put a little too much work into mine... Seeing that everyone else's solutions are extremely short. It didn't take me long at all to figure this out but my process I guess was longer than necessary. Anyways, here is my solution.

Equation 1: X + Y = 55 Equation 2: X - Y = 27 The first thing I did was determine which variable was larger and saw that X was larger due to the fact that if X has to be larger than Y in order for the solution to be a positive number in the second equation. So now we know what we are after, the value of X.

I started with Equation 2(Eq2) because that was were we got our information and it seemed the easier one to start with. I add Y to both sides to cancel Y out and also find a substitute value for X.

X - Y(+Y)= 27 + Y X = 27 + Y

I then plugged in the value of X into Eq1.

(27 + Y)+Y = 55

I simplified it.

27 + 2Y = 55

Then I begin to isolate Y by bringing the value 27 to the other side .

(27 - 27) + 2Y = (55 - 27)

Leaves us with...

2Y = 28

Then isolate Y by dividing by 2 on each side to cancel out the 2 attached to Y.

2Y / 2 = 28/ 2

Which gives us...

Y= 14

Now that we have found the value of Y we can find X, the solution and the larger number of the pair by plugging Y into one of the equations. In this example I use Eq1 to find the solution but you can use Eq2 as well.

X - 14 = 27

Isolate X.

X (- 14 + 14) = (27 + 14)

Therefore... X = 41.

Check your work by plugging the values into both problems and seeing that they both fit...

Equation 1: 41 + 14 = 55 Equation 2: 41 - 14 = 27

Now that you have both the variables,

X = 41 Y= 14

Submit the value of X as your solution because it is the larger of the pair as predicted in the beginning.

The end.

Out of curiosity, why did you solve for y since you already knew x was larger logically from Eq.2? By adding the two equations you would isolate x (2x=82). If you had been the larger you could have subtracted the two equations and gotten 2Y=28.

Neill Conroy - 5 years, 9 months ago
Ric Phillips
Sep 1, 2015

To not leave anything out....

The general strategy for these kinds of problem is,

1: Create one new equation using all the terms from both.

2: Eliminate the terms you don't want from the new equation.

3: Isolate the term whose value you want - so that it is all alone one side of the equation.

4: Calculate the value of the term whose value you want.


1: Create one new equation using all the terms from both.

There is no arithmetic that does this, you just need to understand how equality works. Let's use addition, but remember subtraction would work too...

(x+y) + (x-y) = 55+27

2: Eliminate the term you don't want - in this case it's y.

The left side of the new equation uses only addition and subtraction so we can loose the bracket and rearrange the terms...

x+x + y-y = 55+27

y-y = 0 which let's us drop the y entirely because x+x+0 is the same as x+x.

x+x = 55+27

3: Isolate the term you do want - so that it is all alone one side of the equation.

We want only one x in the whole equation and x + x is the same as 2x so let's do that...

2x = 55+27

And we want to get x on one side by itself. To get to just x on the left side we have to divide 2x by 2 which equals x. But that will ruin the equality so we have to divide the right side by 2 as well.

x/2 = (55+27) / 2

x = (55+27) / 2

4: Calculate its value.

x = 82 / 2

x = 41

All done.

Jeffrey White
Aug 30, 2015

I won't lie, but I guessed the answer.

Shekhar Chaudhary
Aug 29, 2015

Solution pretty simple 😊

Michelle Wanha
Aug 29, 2015

X=55-Y...1 & -Y=27-X...2 Substitute equation 1 into equation 2 Therefore: -Y=27-(55-y) ➡ -Y-y=27-55+y ➡ -2y=28 ➡ y=14 Therefore: Substitute y into equation 1 X=55-14 ➡ x=41 Therefore: x is the largest variable at 41.

Jonny Clark
Aug 28, 2015

x + y = 55 x - y = 27

55 - 27 = 28 28 / 2 = 14 27 + 14 = 41

x = 41

Sinnatra Clegg
Aug 28, 2015

if you know algebra you will find this easy as pie

So, I thought it was 28. Obviously I wasn't thinking Algebra wise but 55 - 27 = 28 .. I feel dumb now.

Janessa Campiou - 5 years, 7 months ago
Mary Ola
Aug 27, 2015

x+y =55 ; x-y=27 ; y=55-x ; x -(55-x)=27 ; 2x=55+27 ; x=82/2 ; x=41

Aniko Ivanyi
Aug 27, 2015

2x + y - y = 82 x= 41

Arianna Gallegos
Aug 23, 2015

55+27=82 82÷2=41 Easy solution

Raluca Militaru
Aug 22, 2015

What can do is solve for one variable first (it doesn't matter which one you chose) x+y=55 => x=55-y x-y=27 Then replace the variable you solved for in the other equation with the amount it equals. x=55-y x-y=27 (55-y)-y=27 Then solve for y: (55-y)-y=27 55-2y=27 -2y=27-55 -2y=-28 2y=28 y=14 Then plug in y into the original equation: x+14=55 x=55-14 x=41

Ethan Aaberg
Aug 19, 2015

Try phrasing the question better, next time. I mean I get that the guy who made it is Indian and thus probably doesn't speak English as a first language (heck, this might have been originally written in Indonesian and just translated poorly), but come on, ". . . which of x,y is larger? Submit your answer as the larger number." is one of the most confusing things I've ever had to decipher. Try " . . . which of the two variables is larger? Submit the larger number as your answer." Put me in the problem-wording-creation field, coach. I'm ready.

Kelsey Thompson
Aug 17, 2015

Difference between 55 and 27 is 28, 28/2=14 27+14=41

x+y=55 - x-y= 27


2y = 28 (obviously it's y=14)

I picked x + y = 55 and substituted y=14 ---> x + 14 = 55 ---> x = 55 - 14 = 41

Igor Mendes
Aug 14, 2015

if y=55-x , we have x- (55-x)=27.==> 2x=27-28 ==> x=-28/2 Then, we have y=55-x=41

Saarisht Thaman
Aug 12, 2015

So simple! Just add the equations and you will get 2x=82 so x=41 and 41+y=55, y=14

Rj Pranav
Aug 11, 2015

x+y=55 x-y=27 after adding this two equations (x+y=55)+(x-y=27) 2x =82 then x=41 as x+y=55 then y=14 as we can see the larger one is x so thats our answer.... :)

Daniel Trotman
Aug 10, 2015

Difference between 55 and 27 is 28, divided by two would give y (14) 27 + 14 = 41, or x

x+y=55 -> (1)

x-y=27 -> (2)

(1)-(2) =

2y=28

y=14

x=55-14=41

William Lake
Aug 6, 2015

Solve for X first (subtract Y and add Y) X=55-Y and
X=27+Y

Therefore 55-Y=27+Y Solve for Y Y=14 (55=27+2Y) Return to X+Y=55
X= 41

Wael Mohamed
Aug 6, 2015

we get the sum of the two equations x+y+x-y=55+27=82 , 2x=82 , x=41

I liked the way it was made confusing...that stmt made me read the question twice !!

Boyce Towell
Aug 4, 2015

Question is invalid. It says which of x,y is larger? Since x-y=27 and 27 is not negative x is always larger. No need to solve.

Niño Muring
Aug 3, 2015

Tip... Subtitute a number given in the choices and look for a number that the sum is equal to 55 and the difference is equal to 27. And Tadaaaah ! XDD

Kristian Iroy
Aug 3, 2015

X - Y = 27
X = Y+ 27 Y+27 +Y = 55 2Y+27 = 55 2Y = 28

Y = 14

X=55-14 X = 41

41+14 = 55 41-14 = 27

BIGGER NUMBER =(SUM+DIFFERENCE)/2 SMALLER NUMBER= (SUM-DIFFERENCE)/2

Chelsea Long
Jul 30, 2015

x+y=55 and x-y=27

If we solve both equations for x, we have:

x=55-y and x=27+y

Since x = both 55-y and 27+y, then we can conclude that 55-y=27+y Now we solve for y:

55-y=27+y (Subtract 27 from both sides.) 28-y=y (Add y to both sides) 28=2y (Divide 2 from both sides.) 14 = y

Now we know y=14, so we can solve for x:

x=55-y x=55-14 x=41

x is the larger number, and x=41, so the answer is 41.

Ceora F
Jul 29, 2015

x+y=55.
-× -x y=55-x

x-y=27

x-(55-x)=27

x+x-55=27

2×=27+55

2×=82

×=41 which is obviously greater than y

Opu Sarwar
Jul 29, 2015

A.T.Q

2x = 82,

x = 41

y = 55-41

= 14

so the largest no. is x = 41.

Jake Hampton
Jul 28, 2015

Easy plug all the numbers into the equation for x because x is obviously the larger quantity solve for y if y is the same in both equations you get your answer lol

Jay Janjwadia
Jul 28, 2015

You can solve it by simultaneous method

David E Mione
Jul 27, 2015

Or, look at the possible answers subtract the amount for y you could have to make the answer true, now apply it to the first problem, does it match? The only one that satisfies both is 41, because 41-14=27 and 41+14=55 Therefore it is 41.

Raj Rawat
Jul 26, 2015

+y and -y get cancel Then 2x=82 X=41

Jake Fitzgibbon
Jul 24, 2015

41–55=14 and 41–14=27

Brandon Selburg
Jul 21, 2015

Although I went a roundabout way of doing it. I got 41.

Pethanatchi Jothy
Jul 21, 2015

2X = 82

x = 41

41+y =55

y = 55-41

y =14

X is greater than y

Look for the value of x using the second equation: [1] x - y = 27 [2] x = 27 +y Substitute the value of x to the first equation: [3] x + y = 55 [4] (27 + y) + y = 55 Find the value of y: [5] 27 +y+y=55 [6] 27+2y=55 [7] 2y = 55 - 27 [8] 2y = 28 [9] 2y/2 = 28/2 y=14 Find the value of x: [10] x + y = 55 [11] x + 14 = 55 [12] x = 55 - 14 x = 41

Adarsh Mahor
Jul 18, 2015

X+y=55. & x-y=27.
So add given equation 2x=82. X=41 41+y=55.
So. Y=14 So greatest is x=41

Hadia Qadir
Jul 18, 2015

x+y=55...1 x-y=27....2 1+2 2x=82 x=82/2=41 answer

Austin Ashmore
Jul 17, 2015

Start from 55 and work your way down. Once you reach 41, you will find that 41+14=55 and 41-14=27

John Barnett
Jul 17, 2015

took me 15 seeconds

Nakul S Prakash
Jul 17, 2015

Just add both sets of eq.

Sandeep N
Jul 16, 2015

X+y=55 X-y=27 +y and -y cancel we get 2x=82 X=82/2=41

Ian Kirk-Ellis
Jul 16, 2015

The difference between the two values is 28. x is constant in both formulae. The difference betwene the two values is also 2y, therefore 28/2 = 14. 55-14 = 41, 27 + 14 = 41 therefore x =41

Yi Faith
Jul 15, 2015

how much a month?

Ibrahim Hashi
Jul 15, 2015

X+Y=55 (1)

X-Y=27 (2)

Obviously X is the larger number.

In (2) X is bigger than Y by 27 : X=27+Y

Then (1) looks like this (27+Y)+Y=55

And since 55-27=28, that's the sum of the 2 Ys

28÷2=14 that's the value of Y

Therefore X=55-14 which equals 41.

To answer the question of the larger the second equations tells that x x is larger....

so we have to find x x

From the equations using Linear Elimination Method

x + y = 55.... ( 1 ) x+y=55 ....(1)

x y = 27.... ( 2 ) x-y=27 ....(2)

From which we get . . . . . 2 x = 82 .....2x =82

x = 41 \therefore \boxed{x=41}

Tyler Koos
Jul 13, 2015

X+y= 55 X-y= 27,

x=55-Y x=27+y

55-Y=27+y

2y=28

Y=14, x=41

Alejandro Ray
Jul 12, 2015

(55 - 27) ÷ 2 = y

55 - y = x

or

27 + y = x

Djoolcy Dantes
Jul 12, 2015

X+Y=55 X-Y=27

-y+y cancels out x+x=2x 55+27=82 2x=82 2x/2 ...82/2 X=41

the easiest one in this case: x + y = 55 (1) x - y = 27 (2) 2x = 82 => x = 82/2 = 41 (here you can verify y to see which is greater but it's pretty clear )

Neeraj Sajith
Jun 29, 2015

1+1=2 i think

Hunter Bosworth
Jun 29, 2015

Omg people put so much thought into this, it's simple substitution..... (x+y=55) solve for x... (x=55-y)... Substitute this new equation for x in the second equation... (x-y=27) becomes... (55-y-y=27) solve for y... (55-2y=27)... (-2y=-28)... (2y=28)... (y=14)... (55-14=41)

Manish Chandra
Jun 24, 2015

By hit and trial... Let X=40,Y=15 ,X+Y=55 ✅ X-Y=25 ❎ Let X=41,Y=14 ,X+Y=55 ✅ X-Y=27 ✅ That's how I solved it !

Dale Cook
Jun 18, 2015

Substituting 55 for x+y, and 27 for x-y, then by the transitive property (x+y)+(x-y) must equal 82: (55+27). Such as (x+y)-(x-y) equals 27. From here you can reduce the first equation to as follows: (x+y)+(x-y) = 82 (x+y)+(x) = 82-y X+x = 82 2x/2 =82/2 X = 41 55-41 = 14 = y To check your work you can take the second equation to solve for y.

This is my first visit to this app and I think it's incredible how so many different people think so differently with the same accuracy for the same results.

Dale Cook - 5 years, 12 months ago

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