Babies born

[anastasios1984]

Each baby born at a certain hospital last week was either a single birth or one of a pair twins. If x is the number of babies born at the hospital last week, is x odd?

i) 33 single births
ii) 3 pairs of twins born

At present I do not have OA. However, this question was one among others I answered wrong at a previous mock test at my Gmat school

My line of reasoning was the below:

S - > single births
T - > twin births
X - > Total babies

S + 2T = X

i) 33 + 2T = X, which can be translated odd + even = odd, so i is SUFFICIENT

ii) S + 2*3 = X, NOT SUFFICIENT

so answer must be A, correct?

[Anurag@Gurome]

My line of reasoning was the below:
...
so answer must be A, correct?

Yes, your reasoning is correct.

However, this can solved without analyzing the statements as well.
We know that x = (Number of single births) + (Number of double births)
Now, number of double births will be always even.

Hence, x = EVEN + Something
If that something is even, x will be even
And if that something is odd, x will be odd

Hence, we just need to know whether the number of single births is even or odd.

The correct answer is A.