Multivariate mystery

Algebra Level 1

The sum of three different numbers is 67. The two larger numbers differ by 7 and the two smaller numbers differ by 3. What is the value of the largest number?


The answer is 28.

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12 solutions

Neogin Floranza
Mar 16, 2014

x+y+z=67 x-y=7 y-z=3 (x=28)

Bagaskoro Yonear
Mar 16, 2014

x < y < z | x + y + z = 67 | z - y = 7 | y - x = 3 | z - x = 10 | x = smallest number, so take the 3 and 10 | 67 - ( 3 + 10 ) = 67 - 13 = 54 | there are three numbers, so | 54/3 = 18 | 18 = smallest number = x | x = 18 | y = x + 3 = 18 + 3 = 21 | z = largest number = x + 10 = 18 + 10 = 28

B D
Mar 10, 2020

a>b>c

a=b+7

b=c+3 => a = c+10

a +b +c=67

c+10+c+3+c=67

3c+13=67

3c=54

c=18

a=c+10

a=18+10

a=28

( x 3 ) + x + ( x + 7 ) = 68 (x-3) + x + (x+7) = 68 x = 21 x + 7 = 28 x = 21 \Rightarrow x+7 = 28

Jingyang Tan
Mar 2, 2015

First remove the 3s and 7s: 67-7-3-3=54(3 of C)

1C=54 divided by 3=18

18+3+7=28 (A)

Anubhav Sharma
Sep 8, 2014

Let the greatest number be x

Let the middle number be y

Let the smallest number be z

x + y + z = 67

x - y = 7 ----------------------------(i)

x = 7 + y-------------------------------(ii)

y - z = 3 ------------------------------(iii)

y = z + 3-------------------------------(iv)

7 + y = x

7 + z + 3 = x

x = z + 10

z = x - 10 --------------------------------------------(v)

x + y + z = 67

x + x - 7 + x - 10 = 67

3x - 17 = 67

3x = 84

x = 84 / 3 = 28

Thus,

largest number is 28

Koushik Nannuri
May 1, 2014

let the numbers be x+7,x,x-3 then x+7+x+x-3=67 solving this we get, 3x=63 from this x=21 then we get numbers 28,21,18 from this the highest number is 28

Yassine Saddok
Mar 19, 2014

x+y+z=67 x-y=7 y-z=3 y+7+y+y-3=67 3y+4=67 3y+4-67=0 3y-63=0 y=63/3=21 x=28 z=18

Khadija Khan
Mar 16, 2014

28+21+18

Saarah Hussain
Mar 16, 2014

Start by finding any random number between 20 and 30, ie: 23. Now we want this to have a difference with 7. 23- 7 = 16. So we now think the first two numbers largest to smallest is 23 and 16. 16-3 = 13. Now it's 23, 16, 13. Add them up, which equals 52. But we want 67. The difference between 67 and 52 is 15, and there are 3 numbers. 15÷3 = 5. Therefore we add each of the numbers (23, 16, 13) by 5; 28, 21, 18. To make sure we have 67, add them up, which equals 67!!!! The largest number in the equation is 28, so the answer is 28!!!!!

Aravind Chiguru
Mar 16, 2014

let a,b,c are three different numbers & a>b>c now according to problem we get z-y=7 &y-x=3 & x+y+z=67 by solving we get x=18,y=21,z=28 largest nmber is 28

Sathi Nagi Reddy
Mar 15, 2014

Let x,y,z be the three distinct numbers with z as largest, y as second largest and x as smaller Lets form the algebraic equations with given conditions: x+y+z=67.........(1) z-y=7..................(2) y-x=3...................(3) (1)+(2): x+2z=74.......(4) (2)+(3): z-x=10..........(5) (4)+(5): 3z=84: z=28 x=18 y=21

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