The ratio of investments of two partners P and Q is 7:5 and the ratio of their profits is 7:10. If P invested the money for 8 months, find for how much time did Q invest the money?
Choose the correct choice from the following answers.
A) 11	B) 10	C) 18	D) 16	E) 12

Rationale: "7 * 5 : 8 * x = 7 : 10 x = 16 answer : d"
Answer: D