The ratio of investments of A and B is 8 : 7 and the ratio of their yearend profits is 20 : 21. If B invested for 12 months, then find the period of investment of A:
Choose the correct answer:
A) 6 months	B) 8 months	C) 10 months	D) 12 months	E) None
Let A invest for x months ; A = 8x months,   B = 7 × 12 = 84 months   8x/84 = 20/21   ⇒ x = 10.   Answer: 10 months
<result>C</result>
The ratio of investments of A and B is 8 : 7 and the ratio of their yearend profits is 20 : 21. If B invested for 12 months, then find the period of investment of A: