Always remember following cases

even + even = even
odd +odd= even
even +odd = odd
odd+even =odd

b is odd or even ?

Statement I

3a+4b=even

4b will always be even weather b is odd or even
3a will also be even, therefore a is even.

Therefore, insufficient.

Statement II

3a + 5b is even

if a is odd b will also be odd, if a is even b will also be even and vice versa.

Therefore, insufficient.

Statement I and II

if a is even, b has to even.

Hence Sufficient.

C is the answer.

parallel_chase this was exactly the route i had chosen to reach to solution

I hope u wanted to say o+o=E

Regards,

eccentric wrote:parallel_chase this was exactly the route i had chosen to reach to solution

I hope u wanted to say o+o=E

Regards,

Yup, exactly. Odd + Odd = Even.

tks