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

What is the rate of interest when the $P.W.$ of $Rs. 1245$ due in $15$ months is $Rs. 1200$? (in $\%$)

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 $\%$)?

Ramesh marks his goods $30 \%$ above cost price. If he sells the item for $Rs. 910$ after allowing a discount of $15 \%$,find his cost price (in $Rs.$).

Successive discounts of $20 \%$ and $10 \%$ are given on an item marked at $Rs. 700$. Find the selling price (in $Rs.$).

$Rs. 20$ is the true discount on $Rs. 260$ due after a certain time. What will be the true discount on the same amount due after half of the earlier time,the rate of interest being the same? (in $Rs.$)