There's something wrong with the question; if a = 2 and b = 2, then a-b and ab are both even, and so are all of the answer choices.mgmt_gmat wrote:If a and b are positive integers such that a - b and ba are both even integers, which of the following must be an odd integer?
A. 2a
B. 2b
C. (a+b)/2
D. (a+2)/2
E. (b+2)/2
odd integer
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One thing is quite lucid that both a and b are even positive integers, because a - b is even when either both a and b are even or both are odd positive integers. But the product of two odd positive integers cannot be even, hence, both a and b are even positive integers.mgmt_gmat wrote:If a and b are positive integers such that a - b and ba are both even integers, which of the following must be an odd integer?
A. 2a
B. 2b
C. (a+b)/2
D. (a+2)/2
E. (b+2)/2
I can prove all the choices as even that easily. Something seems to be missing here.
The mind is everything. What you think you become. -Lord Buddha
Sanjeev K Saxena
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Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001
www.manyagroup.com
