Variable a, b are integers. If (a x b) - (a + b) is odd, which of the

Question

Variable a, b are integers. If (a x b) - (a + b) is odd, which of the following statements is true?
I. a is odd, b is odd
II. a is even, b is odd
III. a is even, b is even

A. I only
B. III only
C. I and II only
D. II and III only
E. I,II and III

TestPrepUnlimited · Answer

The question should be rephrased as "which of the following COULD be true?".

I. Plug in a = 1, b = 1 and we see the result is -1 which is odd. Could be true.
II. Plug in a = 2, b = 1 and we see the result is -1 which is odd. Could be true.
III. Plug in a = 2, b = 2 and we see the result is 0 which is even. False.

Ans: C

hvpatel1993 · Answer

any alternate method to solve this question ?

CrackverbalGMAT · Answer

There are 3 statements carrying I. Lets start with I.

I says a is odd, b is odd

Then a X b is odd and a + b is even

Odd - even is odd.
I is true. Eliminate B & D not carrying I.

C & E both have II, so lets start off with III.

III. a is even, b is even

So a x b is even and a + b is even

Even -Even is even.
III is false. Eliminate D & E.
 (option c)

D.S
GMAT SME

Variable a, b are integers. If (a x b) - (a + b) is odd, which of the

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GMAT Problem Solving (PS) Questions

Variable a, b are integers. If (a x b) - (a + b) is odd, which of the

Prep Toolkit

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