The value of a machine depreciates at the rate of $12\%$ per annum. It was purchased $3$ years ago. Its present value is $Rs. 29644.032$. What was the purchase price (in $Rs.$) of the machine?

Find the compound interest (in ₹) on ₹ $15625$ for $9$ months at $16 \%$ per annum compounded quarterly.

The compound interest earned by Shivam on a certain amount at the end of $2$ years at the rate of $8 \, p.c.p.a.$ was $Rs. 1414.4$. What was the total amount that Shivam got back at the end of $2$ years in the form of principal plus interest earned (in $Rs.$) (in $.4$)?

There is a $40 \%$ increase in an amount in $8$ years at simple interest. What will be the compound interest (in rupees) on ₹ $30000$ after $2$ years at the same rate?

The difference between the compound interest and simple interest on a certain sum at $3 \%$ per annum for $3$ years is ₹ $27.27$. The sum is (in ₹):

$A$ sum of ₹ $12,000$ deposited at compound interest becomes double after $5$ years. After $20$ years,it will become (in ₹): (in $,000$)