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 $\%$)?

$B$ borrows ₹ $5,000$ from $A$ at $6 \%$ p.a. simple interest and lends it to $C$ at compound interest of $10 \%$ p.a. If $B$ collects the money back from $C$ after $2$ years and repays $A$,the profit made by $B$ in the transaction is (in ₹):

$A$ man borrows money at $3 \%$ per annum interest payable yearly and lends it immediately at $5 \%$ interest (compound) payable half-yearly and thereby gains ₹ $330$ at the end of the year. The sum borrowed (in ₹) is

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?

Which information given below is sufficient to know the principal amount if the difference between the $C.I.$ and $S.I.$ for $2$ years is $18$?
$(I)$ The rate is same at which an amount of $Rs. 1000$ becomes $1120$ in $2$ years under $S.I.$
$(II)$ The principal is $Rs. 2000$.

The difference between simple interest and compound interest (in ₹) on ₹ $1250$ for $2$ years at $4 \%$ $p.a.$ is