Calculate the amount and the compound interest by using the formula for compound interest.

Principal             Rate of interest         Time (in years)

$₹1000$               $10\% \mathrm{p}.\mathrm{a}$                     $3$

Calculate the amount and the compound interest by using the formula for compound interest.

Principal             Rate of interest         Time (in years)

$₹8000$           $10\%$ half-yearly                $1\frac{1}{2}$

Calculate the amount and the compound interest by using the formula for compound interest.

Principal             Rate of interest         Time (in years)

$₹700$              $20\%$ half-yearly              $1\frac{1}{2}$

Sangeeta lent $₹40960$ to Amar to purchase a shop at $12.5\%$ per annum. If the interest is compounded  semi-annually, find the interest paid by Amar after  $1\frac{1}{2}$ years. Give the answer in $₹$.

Sudhir lent $₹2000$ at compound interest at $10\%$ payable yearly, while Prashant lent $₹2000$ at compound interest at $10\%$ payable half-yearly.  Find the difference in the interest received by  Sudhir and Prashant at the end of one year. Give the answer in$₹$. 

How much will $₹25000$ amount to in $2$ years at compound interest, if the rates for the successive years be $4$ and $5$ per cent per year? Give the answer in$₹.$ 

Umesh set up a small factory by investing $₹40,000$. During the first three successive years his profits were $5\%, 10\%$ and $15\%$ respectively. If each year the profit was on the previous year's capital, calculate his total profit in $₹$.

Himachal Pradesh State Electricity Board issued in July $1988$, $20$ year bonds worth $₹6.25$ crore. The issue price of each bond is $₹100$ and it carries an annual interest of $11.5\%$, compounded half-yearly. Jasbir invested $₹5000$ in these bonds. Find the amount that he gets on maturity of the bonds in $2008$. Give the answer in$₹$. 

A district contains $64000$ inhabitants. If the population increases at the rate of $2\frac{1}{2}\%$ per annum, find the number of inhabitants at the end of $3$ years.