A man borrows ₹ $25000$ at $20 \%$ compound interest. At the end of every year he pays ₹ $5000$ as part repayment. How much (In ₹) does he still owe after three such instalments?

What will be $C.I.$ (In $Rs.$) on an amount of $Rs. 10000$ at the rate of $20$ $p.c.p.a.$ in two years if the interest rate is compounded half yearly?

On a certain principal if the simple interest for two years is ₹ $1400$ and compound interest for the two years is ₹ $1449,$ what is the rate of interest (In $\%$) ?

A sum of money placed at compound interest doubles itself in $5$ years. It will amount to eight times itself at the same rate of interest in (In $years$)

If the compound interest on a sum for $2$ years at $12 \frac{1}{2} \%$ per annum is ₹ $510,$ the simple interest (In ₹) on the same sum at the same rate for the same period of time is.