The present worth of $Rs. 920$ due at the end of $3$ years at $5\%$ simple interest per annum is (in $Rs.$)

The banker's gain on a sum due $2$ years hence at $10 \%$ p.a. is $Rs. 120$. The banker's discount is (in $Rs.$)

$A$ bill which is due at the end of $4 \text{ years}$ is now worth $Rs. 575$,but if it is due in $2 \frac{1}{2} \text{ years}$,it would now be worth $Rs. 620$. The sum of the bill is (in $Rs.$)

While selling a watch,a shopkeeper gives a discount of $5 \%$. If he gives a discount of $7 \%$,he earns $Rs. 15$ less as profit. The marked price of the watch is (in $Rs.$):

The true discount on a bill due $10$ months hence at $15 \%$ per annum is $Rs. 225$. The amount of the bill is (in $Rs.$)

$1$ packet of biscuits costs $Rs.\, 16$,but a pack of $4$ of the same packets of biscuits costs $Rs.\, 56$. What is the effective discount (in $\%$) on the pack?