The compound ratio of 1:4, 3:2 and 4:5?  Choose the correct answer
A) 1 : 9 B) 1 : 7 C) 1 : 2 D) 3 : 10 E) 1 : 4

Rationale: "1 / 4 * 3 / 2 * 4 / 5 = 3 / 10 = 3 : 10 answer : d"
Answer: D