The banker's discount on $Rs. 2400$ at $12 \%$ p.a. is the same as the true discount on $Rs. 2520$ for the same time and at the same rate. The time is (in months):

The holder of a bill for $Rs. 17850$ nominally due on $May 21, 1991$ received $Rs. 357$ less than the amount of the bill by having it discounted at $5 \%$. When was it discounted?

$A$ 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 $Rs.$)

After giving $20 \%$ discount on an article there is a profit of $20 \%$. What will be the profit percent when no discount is given (in $\%$)?

The marked price of an article is twice the cost price. For a gain of $30 \%$,what should be the discount percentage?

If the compound interest on a certain sum of money for $2 \text{ years}$ at $4 \%$ per annum is $Rs. 45.90$,the true discount on the same amount of money due $2 \text{ years}$ hence at $4 \%$ per annum simple interest is (in $Rs.$):