If $64000$ is deposited at $5 \%$ compound interest for a period of $18$ months,interest being compounded half-yearly,find the amount.

An amount of money at compound interest grows up to $Rs. 3840$ in $4$ $years$ and up to $Rs. 3936$ in $5$ $years$. Find the rate of interest (in $\%$)?

$A$ sum of money lent at compound interest for $2 \, yr$ at $20 \% \, p.a.$ would fetch $Rs. 964$ more,if the interest was payable half-yearly than if it was payable annually. What is the sum (in $Rs.$)?

$A$ sum of $Rs. 1000$ after $3 \, \text{years}$ at compound interest becomes a certain amount that is equal to the amount that is the result of a $3 \, \text{year}$ depreciation from $Rs. 1728$. Find the difference between the rates (in $\%$) of $C.I.$ and depreciation? (Given $C.I.$ is $10 \% \, p.a.$)

$A$ sum of money,deposited at some rate $p.c.p.a.$ of compound interest,doubles itself in $4$ years. In how many years will it become $16$ times of itself at the same rate?

$A$ sum of money is paid back in two annual instalments of ₹ $17,640$ each,allowing $5 \%$ compound interest compounded annually. The sum borrowed was (in ₹):