(A/8) + (2/9) = (B/72)

In the equation above, if A represents a positive integer which of the following could be the value of B?

A) 7

B) 16

C) 18

D) 26

E) 34

, so you know that A and B are wrong. In order to get that common denominator of 72, the fraction must be multiplied by . That means whatever you’re adding to 16 in the numerator must be a multiple of 9. So, 16 + [some multiple of 9] = B.

C and D don’t work, because 18 – 16 = 2, which isn’t a multiple of 9, and 26 – 16 = 10, which also isn’t a multiple of 9.

E works, because 34 – 16 = 18, which is a multiple of 9.