In a certain school, the ratio of boys to girls is 5 to 13. If there are 64 more girls than boys, how many boys are there?
Choose the most appropriate option:
A) 27
B) 40
C) 45
D) 72
E) 117

Rationale: the ratio of b to g is 5 : 13 and the other data point is g are more than boys by 64 . . . looking at the ratio we can say that the 8 ( 13 - 5 ) extra parts caused this diff of 64 . so 1 part corresponds to 64 / 8 = 8 and so 5 parts correspond to 5 * 8 = 40 . b
Answer: B