$A$ sum of money will double itself in $16$ years at simple interest at an yearly rate of (in $\%$):

$A$ certain sum of money amounts to ₹ $2200$ at $5 \%$ $p.a.$ rate of interest,and ₹ $2320$ at $8 \%$ interest in the same period of time. The period of time (in years) is:

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?

The simple interest on a certain sum of money at the rate of $5 \%$ per annum for $8$ years is ₹ $840$. What is the rate of interest per annum for which the same amount of interest can be received on the same sum after $5$ years (in $\%$)?

What is the present worth (in ₹) of ₹ $132$ due in $2$ years at $5\%$ simple interest per annum?

The rate percent per annum at which ₹ $1200$ amounts to ₹ $1440$ in $4$ years is: