If the ratio of a to b is 7 to 3 and the ratio of b to c is 1 to 5, what is the ratio of a to c?	Choose the correct answer
A) 4 / 15 B) 1 / 3 C) 2 / 5 D) 4 / 5 E) 7 / 15

Rationale: "a : b = 7 : 3 - - 1 b : c = 1 : 5 = > b : c = 3 : 15 - - 2 from 1 and 2 , we get a : c = 7 : 15 answer e"
Answer: E