If after giving a discount of $18 \%$,a book is sold for $Rs. 1599$,what will be the marked price (in $Rs.$) of the book?

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 discounts offered on a shirt of $Rs. 500$ and a pair of trousers of $Rs. 1000$ are $20\%$ and $40\%$ respectively. If Ajay bought $3$ shirts and $3$ pairs of trousers,what was the effective discount (in $\%$) he received?

$A$ has to pay $Rs. 220$ to $B$ after $1$ year. $B$ asks $A$ to pay $Rs. 110$ in cash and defers the payment of the remaining $Rs. 110$ for $2$ years. $A$ agrees to it. Counting the rate of interest at $10\%$ per annum in this new mode of payment,which of the following is true?

The marked price of a laptop is $Rs. 12000$. In a clearance sale,it is sold at a discount of $15\%$,incurring a loss of $4\%$. What is the cost price of the laptop? (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 $Rs.$)?