Mr. Gupta deposits ₹ $3000$ in a bank at $10 \%$ $p.a.$ and ₹ $5000$ in another bank at $8 \%$ $p.a.$. The rate of interest (in $\%$) for the whole sum is

$A$ certain sum of money amounts to $Rs. 756$ in $2$ $years$ and to $Rs. 873$ in $3.5$ $years$. Find the rate of interest (in $\%$)?

Income of Hemant was Rs. $4000$. In the first $2$ years,his income decreased by $10\%$ and $5\%$ respectively,but in the third year,the income increased by $15\%$. What was his income (in Rs.) at the end of the third year?

$A$ lends ₹ $2500$ to $B$ and a certain sum to $C$ at the same time at $7 \%$ $p.a.$ simple interest. If after $4$ $years,$ $A$ altogether receives ₹ $1120$ as interest from $B$ and $C,$ then the sum lent (in ₹) to $C$ is

$A$ sum of money at simple interest becomes four times in $24$ years. The rate per cent of interest per annum is

$A$ sum of money will double itself in $16$ years at simple interest at an yearly rate of (in $\%$):