The annual instalment that will discharge a debt of ₹ $4200$ due in $5$ years at $10 \%$ simple interest (in ₹) is:

Kavita invested $\frac{1}{3}$ of her money at $4 \% \text{ p.a.}$,$\frac{1}{4}$ at $3 \% \text{ p.a.}$,and the rest at $5 \% \text{ p.a.}$ She received an annual interest of $Rs. 500$ on her money. Find the total money invested (in $Rs.$).

$A$ sum of money amounts to ₹ $9,800$ after $5$ $years$ and ₹ $12,005$ after $8$ $years$ at the same rate of simple interest. The rate of interest (in $\%$) per annum is

$A$ sum of $Rs. 15000$ amounts to an interest of $Rs. 4500$ in $5$ years. What is the rate of interest (in percentage)?

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?

$A$ sum of money invested at $S.I.$ accrued to $Rs. 800$ in $3$ years and to $Rs. 840$ in $4$ years. The rate of interest (in $\%$) per annum is: