If the ratio of a to b is 2 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 / 15	D) 4 / 5	E) 7 / 6

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