A and B are partners in a business. A contributes 1/4 of the capital for 15 months and B received 2/3 of the profit. For how long B’s money was used?
Select the correct option:  A) 4 months  B) 6 months  C) 8 months  D) 10 months  E) none

Rationale: "sol . let the total profit be rs . z . then , b ’ share = rs . 2 z / 3 , a ’ s share = rs . [ z - 2 z / 3 ] = rs . z / 3 ∴ a : b = z / 3 : 2 z / 3 = 1 : 2 . let the total capital be rs . x and suppose b ’ s money was used for x months . then , [ 1 / 4 x * 15 ] / [ 3 / 4 x * y ] = 1 / 2 ⇔ y = [ 15 * 2 / 3 ] = 10 . thus , b ’ s money was used for 10 months . answer d"
Answer: D