Twice a number is 3 times the square of the number less than one. If

Question

Twice a number is 3 times the square of the number less than one. If the number is positive, what is the value of the number?

(A) 1

(B) 1/2

(C) 1/3

(D) 2/3

(E) 3/2

Word problems are tricky, and it can be especially tricky to translate from words to math. For a discussion of this topic, as well as the OE for this particular question, see:
Intro to GMAT Word Problems, Part 1: Translating from Word to Math

Mike :-)

Abhishek009 · Accepted Answer

2x  =  1  -  3x^2

Now, try to solve using the options , its only a 30 seconds job..

\frac{2}{3}  =  1  - \frac{1}{3}

Answer will definitely be (C)

apoorvasharma13 · Answer

Hi Mike.
Why can't it be interpreted as :
2x = 3(1-x^2)

Thanks.

Abhishek009 · Answer

It is given -    3 times the square of the number   less than one.

daludada · Answer

In such problems, addition, multiplication are not issues. The core issue is with subtraction.

The first entity is to be subtracted with the second entity. For Eg....

A less than B means B-A

Three times the number less than 1 means 1-3x (X being the number)

ScottTargetTestPrep · Answer

The rather odd wording “3 times the square of the number less than one” actually means to subtract 3 times the square of the number from one. Thus, we can create the equation:

2n = 1 - 3n^2

3n^2 + 2n - 1 = 0

(3n - 1)(n + 1) = 0

n = -1 or n = 1/3

Since n is positive, n = 1/3.

Answer: C

IHS · Answer

I hope GMAT stays true to their principles of sentence construction so that such horrible question statements only stay in GMAT club forum.

Posted from my mobile device

Regor60 · Answer

This is just a poor question because it trades on the ambiguity of whether the "3 times" applies to the square of the number to be determined or the result of the square being subtracted from one.

There is no standardized interpretation of this language and that's why certain mathematical ideas are best communicated with the language of mathematics.

Kinshook · Answer

Twice a number is 3 times the square of the number less than one. If the number is positive, what is the value of the number?

Let the number be x.

2x = 1 - 3x^2
3x^2 + 2x - 1 = 0
3x^2 + 3x - x - 1 = 0
(x+1)(3x - 1) = 0
x = 1/3 ; since x = -1 is not positive

IMO C

Twice a number is 3 times the square of the number less than one. If

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Twice a number is 3 times the square of the number less than one. If

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