The ratio of investments of two partners P and Q is 7:5 and the ratio of their profits is 7:13. If P invested the money for 5 months, find for how much time did Q invest the money?
Options: A) 19 B) 17 C) 13 D) 10 E) 12

Rationale: "7 * 5 : 5 * x = 7 : 13 x = 13 answer : c"
Answer: C