If ₹ $640$ amounts to ₹ $832$ in $2$ years,what will ₹ $860$ amount to in $4$ years at the same rate of interest per annum (in ₹)?

Reena took a loan of ₹ $1,200$ with simple interest for as many years as the rate of interest. If she paid ₹ $432$ as interest at the end of the loan period,what was the rate of interest?

Sumit lent some money to Mohit at $5 \%$ $p.a.$ simple interest. Mohit lent the entire amount to Birju on the same day at $8 \frac{1}{2} \%$ $p.a.$ In this transaction,after a year Mohit earned a profit of ₹ $350.$ Find out the sum of money (in ₹) lent by Sumit to Mohit.

Mr. Thomas invested an amount of $Rs. 13,900$ divided in two different schemes $A$ and $B$ at the simple interest rate of $14 \%$ $p.a.$ and $11 \%$ $p.a.$ respectively. If the total amount of simple interest earned in $2$ $years$ be $Rs. 3508$,what was the amount (in $Rs.$) invested in Scheme $B$?

If the simple interest on a certain sum of money is $\frac{4}{25}$ of the sum and the rate per cent equals the number of years,then the rate of interest (in $\%$) per annum is

The population of a town in $2009$ was $125000$. It increases by $10 \%$ per year. What is the population after $3$ years?