GMAT TIGER wrote:
11. If a and b are integers, is b even?
(1) 3a + 4b is even
(2) 3a + 5b is even
C. No need for calculations really.
1: notice that 3a+4b could be E+E and... thats it. 3a CANNOT be odd or 3a+4b would be odd. So keep that in mind from S1 that a must be even. (dont carry it to S2 though
2: 3a+5b. we can have E+E or O+O. so this is insuff.
Now together we know that a is even. So 5b must be even or 3a+5b would not be even. thus B must be even.