$A$ lent ₹ $6000$ to $B$ for $2$ $years$ and ₹ $1500$ to $C$ for $4$ $years$ and received altogether from both ₹ $900$ as simple interest. The rate of interest is (in $\%$):

What annual instalment (in $Rs.$) will discharge a debt of $Rs. 1092$ due in $3$ years at $12 \%$ simple interest?

If the simple interest of ₹ $1$ for $1$ month is $1$ paisa,then the rate per cent per annum will be:

Sumit lends ₹ $10000$ for $2$ $years$ at $20 \%$ per annum simple interest. After $1$ $year,$ he receives ₹ $6000$. How much (in ₹) will he receive next year?

The difference between the interest received from two different banks on $₹ 5,000$ for $2$ $years$ is $₹ 25$. The difference between their rates is (in $\%$):

Asmita invests an amount of $Rs. 9535$ at the rate of $4\%$ per annum to obtain a total amount of $Rs. 11442$ on simple interest after a certain period. For how many years did she invest the amount to obtain the total sum?