A rectangular with dimensions 24 inches by 42 inches . . .

Hi Vincen,

We're told that a rectangular with dimensions 24 inches by 42 inches is to be divided into SQUARES of EQUAL size. We're asked to find the answer that COULD be a length of a side of the squares. We can solve this question by TESTing THE ANSWERS.

To start, the word 'could' means that there's more than one possible answer - but only one of the five answer choices will 'fit' what we're told. We're thinking about SQUARES and we're meant to use the ENTIRE rectangle - so there can't be any 'leftover' space. Thus, whatever the dimension of the square ends up being, a multiple of that dimension MUST cover the entire 24 inches and 42 inches of the rectangle.

Only 3 of the answer choices divide evenly into 24 (4, 6 and 8). Eliminate Answers C and E.
Of those 3 remaining answers, only one divides evenly into 42 (6). Eliminate Answers A and D.
Thus, the squares must be 6x6 --> and that would yield 28 squares in the given rectangle (these last couple of steps are technically unnecessary, but prove the correct answer).

Final Answer: B

GMAT assassins aren't born, they're made,
Rich

Vincen wrote: ↑

Tue Nov 28, 2017 6:37 am

A rectangular with dimensions 24 inches by 42 inches is to be divided into squares of equal size. Which of the following could be a length of a side of the squares?

a) 4 inches
b) 6 inches
c) 7 inches
d) 8 inches
e) 10 inches

The OA is B.

How can I find the correct answer? Can any expert give me some help? Please.

The side length of squares must be a common factor of 24 and 42. Since only 6 (of all the given choices) is a common factor of 24 and 42, choice B is the correct answer.

Answer: B