$A$ man buys a watch for ₹ $1950$ in cash and sells it for ₹ $2200$ at a credit of $1$ $year$. If the rate of interest is $10 \%$ $p.a.$,what is his profit or loss?

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

$A$ person lent ₹ $10000$ to $B$ for $3$ $years$ and ₹ $6000$ to $C$ for $4$ $years$ on simple interest at the same rate of interest and received ₹ $5400$ in all from both of them as interest. What is the rate of interest (in $\%$)?

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 ₹)

The annual payment that will discharge a debt of ₹ $47250$ due in $3$ years at the rate of $5 \%$ simple interest per annum is:

$A$ lent ₹ $6000$ to $B$ for $2$ $years$ and ₹ $1500$ to $C$ for $4$ $years$ and received altogether from both ₹ $900$ as simple interest. The rate of interest is (in $\%$):