What amount (in $Rs.$) would a man have received on a principal of $Rs. 4000$ after $2$ years at a simple interest rate of $5$ $p.c.p.a.$?

$A$ sum was put at simple interest at a certain rate for $4$ $years$. Had it been put at $2 \%$ higher rate,it would have fetched ₹ $56$ more. Find the sum (In ₹).

If a sum of money at simple interest doubles itself in $6$ years,it will become four times in how many years?

The simple interest on a sum of money is $\frac{1}{9}$ of the principal and the number of years is equal to the rate per cent per annum. The rate per cent per annum is equal to

The rate percent per annum at which ₹ $1200$ amounts to ₹ $1440$ in $4$ years is:

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?