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

$Rs.\, 20$ is the true discount on $Rs.\, 210$ due after a certain time. What will be the true discount on the same sum due after half of the former time,the rate of interest being the same? (in $Rs.$)

The price of an article is cut by $42 \%$. To restore it to its original value,the new price must be increased by (in $\%$):

Find the present worth of a bill of $Rs.\, 3720$ which is due for $2\, years$ at $12 \%$ compound interest,being compounded annually. (in $Rs.$)

If the simple interest on $Rs. 2000$ at $5\%$ $p.a.$ is equal to the true discount on $Rs. 2500$ for the same time and at the same rate,the time is (in $years$)