RPH Editorial Team Solutions for Exercise 1: EXERCISE

If $Rs. 900$ amounts $Rs. 1,080$ in $4$ years at simple interest, what sum will amount to $Rs. 1,275$ in $5$ years at the same rate?

A sum of money doubles itself in $7$ years. In how many years it will become four fold?

A certain sum of money amounted to $Rs. 575$ at $5\%$ in a time in which $Rs. 750$ amounted to $Rs. 840$ at $4\%$. The rate being the simple interest. What was the sum?

$\mathrm{Rs}.4,000$ is divided into two parts such that if one part be put at $3\%$ and the other at $5\%$. The annual interest from both the investments be $\mathrm{Rs}.144$. Find the first part?

A sum of money amounts to $Rs. 767$ in $3$ years and $Rs. 806$ in $4$ years at the rate of $6\%$. What is the sum?

In how many years will a sum of money double itself at $12\%$ per annum on simple interest?

What annual payment will discharge a debt of $Rs. 580$ due in $5$ years, the rate being $8\%$ per annum?

A lent $Rs. 600$ to B for $2$ years and $Rs. 150$ to C for $4$ years and received altogether from both $Rs. 90$ as simple interest. The rate of interest is _____.