The true discount on a certain bill due for nine months at $4 \%$ simple interest is $Rs.\, 150$. Find the amount of the bill (in $Rs.$).

The true discount on a bill due $10$ months hence at $15 \%$ per annum is $Rs. 225$. The amount of the bill is (in $Rs.$)

An article is sold for $Rs. 6552$ after a discount of $22 \%$. What is the marked price (in $Rs.$) of the article?

$A$ trader marks the sale price $25\%$ more than the cost price and gives a $10\%$ discount at the time of selling. The gain percent is (in $\%$)

The present worth of $Rs. 220.50$ due in $2$ years reckoning compound interest at $5 \%$ per annum is (in $Rs.$):

$A$ watch dealer pays $10 \%$ customs duty on a watch which costs $Rs.\, 500$ abroad. He desires to make a profit of $20 \%$ after giving a discount of $25 \%$ to the buyer. The marked price should be (in $Rs.$)