Delhi Police Constable Exam Model Paper 9

Given:
Investment ratio of A and B is 9 ∶ 7
Ratio of their annual profit is 3 ∶ 2
Time period of A’s investment is 7 months
Concept:
The ratio in which profit is obtained
⇒ (Investment of A × time period of A) ∶ (investment of B × time period of B)
Calculation:
Let, the investment made by A is 9x and by B is 7x
And also let the time period of B is y(Investment of A × time period of A) ∶ (investment of B × time period of B)
⇒ (9x × 7) ∶ (7x × y)
Now comparing the ratio with the given ratio of their profit
⇒ $\left[\frac{\left(9\mathit{x}\times 7\right)}{\left(7\mathit{x}\times \mathit{y}\right)}\right]=\left(\frac{3}{2}\right)$
⇒ $\left(9\mathit{x}\times 7\right)\times 2=\left(7\mathit{x}\times \mathit{y}\right)\times 3$
⇒ $\left(18\mathit{x}\times 7\right)=\left(21\mathit{x}\mathit{y}\right)$
⇒ $\mathit{y}=\frac{\left(18\mathit{x}\times 7\right)}{\left(21\mathit{x}\right)}$
⇒ $\mathit{y}=6$
∴ Time period of Investment of B = 6 months