You don't need to say a thing Part 3

Logic Level 1

Think of any positive number. Multiply it by itself and subtract negative 3 from it. Then add the original number four times. Divide your resultant number by one more than the original number. Lastly, take the resultant number and subtract off the original number. I know what number you have. What must it be?

4 2 1 3

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

5 solutions

Let x x be the number. Now, by multiplying it by itself we obtain x 2 x^2 , now by subtracting 3 -3 we have x 2 + 3 x^2+3 . Adding four times the number: x 2 + 4 x + 3 x^2+4x+3 , but it can also be ( x + 1 ) ( x + 3 ) (x+1)(x+3) . Finally, dividing it by one more than the original number: ( x + 1 ) ( x + 3 ) x + 1 \dfrac{(x+1)(x+3)}{x+1} , or x + 3 x+3 since x x is positive, and subtracting the original number: 3 \boxed{3} .

I don't seem to get the solution when I picked '2'

Jorge Herrera - 5 years, 9 months ago

Log in to reply

The only explanation can be that you subtracted 3 instead of subtracting -3 which would ultimately give you +3.

Tessa Piovesan - 5 years, 2 months ago

Log in to reply

Why did it not just say add 3 to begin with?

Trenton Wheeler - 4 years, 12 months ago

2×2=4, 4+3=7, 7+(2×4)=15, 15/(2+1)=5, 5-2= 3

Cyril Joy - 5 years, 1 month ago

yeah for me too

Avinash Kamath - 5 years, 3 months ago

2 doesn't work, aswell as one

That happened to me the first time as well. But you're subtracting a negative 3, meaning you're adding 3 (- + - = +). Therefore: (2x2=4) (4+2+2+2+2=12) (12-(-3)=15) (15/3=5) (5-2=3) 3 is your answer.

Bailey Mcneil - 5 years, 3 months ago

If your original number is 2 the result is one which makes it all wrong

Roniel Hernandez - 5 years, 9 months ago

Log in to reply

The same thing goes to 1

Roniel Hernandez - 5 years, 9 months ago

Log in to reply

1 also works. I think you made a mistake in your math somewhere

Mary-Mae Humphrey - 5 years, 7 months ago

Log in to reply

@Mary-Mae Humphrey Please explain?

Avinash Kamath - 5 years, 3 months ago

Log in to reply

@Avinash Kamath You must have misunderstood and miscalculated the part of "Subtract negative 3".

Saya Suka - 2 weeks, 2 days ago

are you sure??

Priyaveda Janitra - 5 years, 8 months ago

I got 1 when I used 2

Nate Carolus - 5 years, 3 months ago

Log in to reply

I got 1 when I used 1

I changed my name. - 2 years, 2 months ago

The actual Procedure => 2 × 2 = 4,
4 - (-3) = 4 + 3 = 7
7 + (2 × 4) = 15
15 / (2 + 1) = 5
5 - 2 = 3.

Perhaps you did like this => 2 × 2 = 4
4 - 3 = 1
1 + (2 × 4)= 9
9 / (2 + 1) = 3
3 - 2 =1.

I would just say ... look twice before you leap.

Avinash Kamath - 4 years, 6 months ago

did you add (-3)

Michael Rocheleau - 5 years, 6 months ago

No, 2 works just the same

Mary-Mae Humphrey - 5 years, 7 months ago

Log in to reply

How is that?

Avinash Kamath - 5 years, 3 months ago

After all the processes the number remaining is 3 => for every value of x the answer we get is 3. Unbounded solution i.e, all positive integers are acceptable.

Mohan Tejesh - 5 years, 8 months ago

It is brilliant, though confusing. You don't need to choose a positive number though, you just need to choose any number that is not -1

Eddie Spagnoli - 5 years, 8 months ago

When subtracting it should have been x^2 - 3, not + 3.

LaShaunte Mitchell - 5 years, 4 months ago

Log in to reply

subtracting negative three means adding 3

David Ridley Officer - 3 years, 4 months ago

The important thing to notice is the (-3) we are really subtracting from any number n squared (the first clue). So the basic equation to set us on the right path is n^2 - (-3) = n^2 + 3. Then we add 4x the original number n to the equation which gives us n^2 + 3 + 4n. Lastly, we take the latest expression and divide it completely by one more than the original number n giving us (n^2 + 3 + 4n) / (n + 1). For algebra connoisseurs, the top expression can be factored as it is a factorable trinomial. In other words, (n + 1) (n + 3) = n^2 + 3n + 1n + 3 OR similarly, by adding the two middle terms 3n and 1n --》(n + 1) (n + 3) = n^2 + 4n + 3.

Notice how factoring the top makes it easier on on the mind or "eyes" to algebraically solve this as (n + 1) (n + 3) / (n + 1) from the above expression, giving us a same term (quantity) in the numerator as well as in the denominator, (n + 1) that therefore cancel out. This leaves the rest as n + 3, which is still unresolved because the last clue given was to lastly subtract the original number n by itself which written out concludes n - n + 3 which is just 3.

Eric Beck - 5 years, 2 months ago

And this is why mixing numerical terms with written terms is a poor idea--maybe logically valid, but definitely not coherent or clear.

Joshua Nesseth - 4 years, 8 months ago

Log in to reply

It is, provided you look carefully, that is.

Avinash Kamath - 4 years, 6 months ago

Log in to reply

I beg to differ. The problem is laid out specifically to exploit the distinction between the written "negative" and the numeric "3", anticipating the omitted nuance when translating them into a unitary referencing system.

In other words, I was merely pointing out the core of the problem is an opportunistic exploitation of the inability for human brains to quickly switch between two different (and usually separate) notational styles--a lesson, as it were, against mixing numbers and words (or any other two distinct lexicographic systems) without extreme care and caution.

[I point that out primarily because I do this quite often, actually...though, I have to admit, it's also because this problem doesn't rely on reason or logic, but merely a common cognitive fallacy. Basically, I find people using parlor tricks to prove how "clever" they are to be a titch annoying sometimes...]

Joshua Nesseth - 4 years, 6 months ago

Log in to reply

@Joshua Nesseth Subtract ==> [ – ]
Negative ==> [ - ]
3 / Three ==> [ 3 ]

Subtract negative 3 ==> – (-3) = + 3 ✓

Saya Suka - 2 weeks, 2 days ago
Anwesha Sinha
Jun 1, 2016

First we take the no. as x. Afterwards,as we follow the given steps, we get a quadratic equation which is :- x^2+4x+3, which on solving, we get 3 as an answer..

Doug Gwyn
Sep 18, 2016

As in a previous puzzle, since the result does not depend on what number was chosen, choose 0 to simplify the arithmetic.

Hadia Qadir
Aug 4, 2015

x^2 - (- 3) x^2 + 4x + 3 x^2 + 4x + 3 / x +1 x + 3 x + 3 - x

3

Saya Suka
May 29, 2021

1) Think of any positive number ==> x

2) Multiply it by itself ==> x × x = x²

3) Subtract negative 3 from it ==> x² – (-3) = x² + 3

4) Add the original number four times ==> x² + 3 + (x × 4) = x² + 4x + 3

5) Divide your resultant number by one more than the original number ==> (x² + 4x + 3) / (x + 1) = x + 3

6) Lastly, take the resultant number and subtract off the original number ==> (x + 3) – x = 3

Universal answer = 3

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...