The banker's gain on a bill due $1$ $year$ hence at $15 \%$ p.a. is $Rs.\, 9$. The true discount is (in $Rs.$)

At $20 \%$ discount,the selling price of an article is $Rs. 2400$. What is the selling price (in $Rs.$) if the discount is $32.5 \%$?

$A$ man buys a single apple for $Rs. 25$. If he were to buy a dozen apples,he would have to pay a total amount of $Rs. 250$. What would be the approximate percent discount he would get on buying a dozen apples?

If on a marked price,the difference between the selling prices with a single discount of $30 \%$ and two successive discounts of $20 \%$ and $10 \%$ is $Rs.\, 72$,then the marked price (in $rupees$) is:

If $Rs. 21$ is the true discount on $Rs. 371$ for a certain time,what is the true discount on the same amount for double that time,the rate being the same in both the cases? (in $Rs.$)

If the true discount on $Rs. 249$ at $5\%$ simple interest $(S.I.)$ is $Rs. 9$,when is the sum due? (in months)