If 15% of 30% of 50% of a number is 117, then what is the number?  Choose the correct answer
A) 5200 B) 3050 C) 4400 D) 4500 E) none of these

Rationale: "let the number be a given , 15 / 100 * 30 / 100 * 50 / 100 * a = 117 = > 3 / 20 * 3 / 10 * 1 / 2 * a = 117 = > a = 10 * 20 * 10 * 2 = 5200 . answer : a"
Answer: A