The simple interest on a sum of money will be ₹ $600$ after $10$ $years$. If the principal is trebled after $5$ $years$,then what will be the total interest (in ₹) at the end of the tenth year?

Shruti borrowed $Rs. 2500$ from her two friends. For one loan she paid $8 \%$ $p.a.$ and for the other $6 \%$ $p.a.$ simple interest. If she paid $Rs. 180$ as total interest for one year,how much did she borrow (in $Rs.$) at $8 \%$ $p.a.?$

If the simple interest on ₹ $x$ at a rate of $a \%$ for $m$ years is same as that on ₹ $y$ at a rate of $a^2 \%$ for $m^2$ years,then $x: y$ is equal to

The population of a town is $11200$. It increases by $25\%$ in the first year and decreases by $15\%$ in the second year. What is the population of the town at the end of $2$ years?

Nitin borrowed some money at the rate of $6 \% \text{ p.a.}$ for the first $3 \text{ years}$,$9 \% \text{ p.a.}$ for the next $5 \text{ years}$,and $13 \% \text{ p.a.}$ for the period beyond $8 \text{ years}$. If the total interest paid by him at the end of $11 \text{ years}$ is $₹ 8,160$,how much money (in $₹$) did he borrow?

In what time (in $years$) will a sum of money double itself at the rate of $20 \%$ per annum simple interest?