In what time (in $years$) will ₹ $8,000$ at $3 \%$ per annum produce the same interest as ₹ $6,000$ does in $5$ years at $4 \%$ simple interest?

$A$ sum of money at compound interest doubles itself in $15$ years. It will become eight times of itself in (in $years$):

The simple interest accrued on an amount of $Rs. 19800$ at the end of $3$ years is $Rs. 7128$. What would be the compound interest (in $Rs.$) accrued on the same amount at the same rate in the same period?

$A$ man borrows $Rs. 5100$ to be paid back with compound interest at the rate of $4 \%$ p.a. by the end of $2$ years in two equal yearly instalments. How much (in $Rs.$) will be each instalment?

If in a certain number of years,₹ $3000$ amounts to ₹ $4320$ at compound interest,in half that time ₹ $3000$ will amount to (in ₹):

The simple interest on a sum of money for $3$ years is ₹ $240$ and the compound interest on the same sum,at the same rate for $2$ years is ₹ $170$. The rate of interest is (in $\%$):