In how much time (in $years$) will a sum of ₹ $9500$ amount to ₹ $17622.5$ at the rate of $4.5 \%$ per annum at simple interest?

The simple interest on a sum of money is $\frac{4}{9}$ of the principal. Find the rate per cent and time,if both are numerically equal.

Mr. Mani invested an amount of ₹ $12000$ at a simple interest rate of $10 \%$ $p.a.$ and another amount at a simple interest rate of $20 \%$ $p.a.$. The total interest earned at the end of one year on the total amount invested was $14 \%$ $p.a.$. Find the total amount (in ₹) invested.

$A$ sum was doubled with $12 \frac{1}{2} \%$ rate of simple interest per annum. The time taken (in years) for that sum is:

If ₹ $640$ amounts to ₹ $832$ in $2$ years,what will ₹ $860$ amount to in $4$ years at the same rate of interest per annum (in ₹)?

$A$ sum of ₹ $2800$ is divided into two parts in such a way that the interest on both the parts is equal. If the first part is lent at $9 \% \text{ p.a.}$ for $5 \text{ years}$ and the second part is for $6 \text{ years}$ at $10 \% \text{ p.a.}$,find the two sums.