A and B started a business jointly. A's investment was thrice the investment of B and the period of his investment was two times the period of investment of B. If B received Rs. 4000 as profit, then their total profit is ?

1Rs. 16000
2Rs. 20000
3Rs. 24000
4Rs. 28000

Answer:- 1

Explanation:-

Solution:

Suppose B invested Rs. x for y months
Then, A invested Rs. 3x for 2y months

\begin{aligned} So, A : B \\ = (3 x \times 2 y) : (x \times y) \\ = 6 x y : x y \\ = 6 : 1 \\ ∴ B's profit : Total profit = 1 : 7 \\ Let the total profit is Rs . x \\ Then, \frac{1}{7} = \frac{4000}{x} \\ \Leftrightarrow x = 28000 \end{aligned}

$\eqalign{ & {\text{So, A}}:{\text{B}} \cr & = \left( {3x \times 2y} \right):\left( {x \times y} \right) \cr & = 6xy:xy \cr & = 6:1 \cr & \therefore {\text{B's profit}}:{\text{Total profit}} = 1:7 \cr & {\text{Let the total profit is Rs}}{\text{. }}x \cr & {\text{Then,}}\frac{1}{7} = \frac{{4000}}{x} \cr & \Leftrightarrow x = 28000 \cr}$