DRDO Multi tasking staff Model paper 3

Let M invested Rs. a in the business.
Ratio of profit = M’s capital × time ∶ N’s capital × time
⇒ 2 ∶ 1 = a × 12 ∶ 12000 × 8
⇒ 2/1 = (a × 12) / (12000 × 8)
⇒ a = 16000
∴ Amount invested by M = Rs. 16000