If a and b are integers greater than 0, is a even?

Question

(1) a = 2b + 1
(2) a^2 + a is divisible by 2

stonecold · Answer

Hers is my solution to this one -->

Given data =>  a and b are positive integers.
We are asked if a is even or not.

Statement 1 => 
a=2b+1= even+odd=odd
hence a is odd

Hence sufficient

Statement 2--> 
a^2+a is even.
a(a+1) is always even irrespective of a being even or odd.

Hence insufficient

Hence A

swatisaini10488 · Answer

If statement b is telling us that a will always be even. 
Then isn't the answer should be D. As both the statements are providing us the answer.

atshy21saraf · Answer

Statement B is not telling us that 'a' is even.
St. 2 says that a(a+1) is even, that says nothing about 'a' as there are two possibilities:
i) if 'a' is even then a+1 is odd (two consecutive integers)......  Yes 
ii) if 'a' is odd, then a+1 is even.......  No 
Both of these conditions satisfy the statement 2, and we have  two different answers  to our main question (is 'a' even). Hence  Insufficient .

On the other hand St. 1 tells us that a is ODD so  NO  (definite answer), hence  Sufficient

If a and b are integers greater than 0, is a even?

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GMAT Data Sufficiency (DS) Questions

If a and b are integers greater than 0, is a even?

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