What will be the difference between simple and compound interest (in ₹) at $10 \%$ per annum on a sum of ₹ $1000$ after $4$ years?

On a sum of money,the simple interest for $2$ years is ₹ $660$,while the compound interest is ₹ $696.30$,the rate of interest being the same in both the cases. The rate of interest (in $\%$) is

The simple interest on a certain sum of money for $3$ years at $8 \%$ per annum is half the compound interest on ₹ $4000$ for $2$ years at $10 \%$ per annum. The sum placed on simple interest (in ₹) is

Which of the statements given below are sufficient to answer the following question?
What is the rate of interest per annum on an investment of $Rs. 800$?
$(I)$ The income from $S.I.$ at the end of $3$ years at the same rate of interest is $19$.
$(II)$ $C.I.$ is $15.76$ more than $S.I.$ on the same sum and same rate in $2$ years.

What will be the amount (in ₹) received on $25000$ at the rate of $20 \%$ per annum compounded yearly for $4$ years?

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?