question_answer

If 15 boys earn Rs. 900 in 5 days, how much will 20 boys earn in 7 days?

A) Rs. 1980                       

B) Rs. 1820

C) Rs. 1780                       

D) Rs. 1680

Correct Answer: D

Solution :

Let the boy will earn Rs. x in 7 days \[\left. \begin{matrix}    15 & : & 20  \\    5 & : & 7  \\ \end{matrix} \right\}\,\,::\,\,900\,\,:\,\,x\] \[x=\frac{20\times 7\times 900}{15\times 5}\] \[=Rs.\,\,1680\]