If ₹ $1000$ is invested at an interest rate of $5 \%$ and the interest is added to the principal every $10$ years,then the number of years in which it will amount to ₹ $2000$ is:

$A$ sum was put at simple interest at a certain rate for $2$ years. Had it been put at $1 \%$ higher rate,it would have fetched ₹ $24$ more. The sum is (in ₹):

$A$ person has left an amount of ₹ $1,20,000$ to be divided between his two sons aged $14$ years and $12$ years such that they get equal amounts when each attains $18$ years of age. If the amount gets a simple interest of $5 \%$ per annum,the younger son's share at present (in ₹) is

$A$ certain sum is invested for a certain time. It amounts to ₹ $450$ at $7 \%$ per annum. But when invested at $5 \%$ per annum,it amounts to ₹ $350$. Find the sum (in ₹).

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

$A$ sum of $Rs. 2540$ is lent out in two parts,one at $12 \%$ and the other at $12.5 \%$. If the total annual return on the total money invested is $Rs. 312.42$,find the money (in $Rs.$) lent at $12 \% \text{ p.a.}$