DRDO Multi tasking staff Model paper 8

Let investment of A = Rs. 7x
Let investment of B = Rs. 9x
Let investment of C is = Rs. 9x × (2/3) = 6x
∴ Weighted ratio of investment of A, B and C
⇒ 7x × 12 : 9x × 12 : 6x × 6
⇒ 84x : 108x : 36x
⇒ 7 : 9 : 3
Let, Profit share of A = 7y
Let, Profit share of B = 9y
Let, Profit share of C = 3y
∴ Total profit = (7y +9y + 3y) = 19y
∴ Total profit = 8400 × (19y/7y) = Rs. 22800