$A$ 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 $Rs. 920$ due at the end of $3$ years at $5\%$ simple interest per annum is (in $Rs.$)

At what percent above the cost price must a person mark the price of an article so that he can enjoy $20 \%$ profit after allowing $20 \%$ discount?

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?

$Rs.\, 20$ 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 $B.G.$ on a certain sum due in $5 \text{ years}$ is $\frac{3}{23}$ of $B.D.$ Here,the rate of interest is (in $\%$):