The rate of simple interest (in $\%$) for which a sum of money becomes $5$ times of itself in $8$ years is:

What sum lent at $10 \%$ per year on $S.I.$ will amount to $Rs. 450$ in $2$ years?

$A$ sum fetched a total simple interest of $Rs. 4016.25$ at the rate of $9 \%$ $p.a.$ in $5$ years. What is the sum (in $Rs.$)?

$A$ 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 $\%$)?

If a sum of ₹ $9$ is lent to be paid back in $10$ equal monthly instalments of ₹ $1$ each,then the rate of interest is

Suhit borrowed a sum of $Rs. 6300$ from Vikas at the rate of $14 \%$ per annum for $3$ years. He then added some more money to the borrowed sum and lent it to Mohit at the rate of $16 \%$ simple interest for the same time. If Suhit gained $Rs. 618$ in the whole transaction,what sum did he lend (in $Rs.$) to Mohit?