$A$ certain sum is invested for a certain time. It amounts to ₹ $450$ at $7 \%$ per annum. But when invested at $5 \%$ per annum,it amounts to ₹ $350$. Find the sum (in ₹).

If the interest on ₹ $12000$ is more than the interest on ₹ $10000$ by ₹ $500$ in $3$ $years$,the rate percent per annum is:

In how many years will a sum of money treble itself at $10 \%$ per annum simple interest?

The rate of interest on a sum is $4 \%$ per annum for the first $2$ years,$6 \%$ per annum for the next $4$ years,and $8 \%$ per annum for the period beyond $6$ years. If the simple interest accrued by the sum for a total period of $9$ years is ₹ $1120$,find the sum. (In ₹)

$A$ sum invested at $5 \%$ simple interest per annum grows to ₹ $504$ in $4$ years. The same amount at $10 \%$ simple interest per annum in $2 \frac{1}{2}$ years will grow to (in ₹):

The simple interest accrued on an amount of $Rs. 2500$ at the end of six years is $Rs. 1875$. What would be the simple interest (in $Rs.$) accrued on an amount of $Rs. 6875$ at the same rate and same period?