If $21 \%$ of an electricity bill is discounted,$Rs. 1817$ is still to be paid. How much was the original bill amount? (in $Rs.$)

The present worth of a sum of money due for $146 \text{ days}$ at $5 \%$ is $Rs. 400$. The sum due is (in $Rs.$)

$A$ dealer purchased an article for $Rs. 900$ and fixes the list price in such a way that he gains $20\%$ after allowing $10\%$ discount. What is the list price (in $Rs.$)?

Find the present worth $(P.W.)$ and the true discount $(T.D.)$ reckoning $6 \%$ per annum simple interest of $Rs. 176$ due in $20 \text{ months}$ time. (in $Rs.$)

Two successive discounts of $a \%$ and $b \%$ on the marked price of an article are equivalent to a single discount of:

$Rs.\, 20$ 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 $Rs.$)