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

$A$ person bought an article for $Rs. 2500$ and sold it the same day for $Rs. 3410$,allowing a credit of $2$ years. If the rate of interest is $12\%$ per annum,then the gain of the man is (in $\%$):

After giving $20 \%$ discount on an article there is a profit of $20 \%$. What will be the profit percent when no discount is given (in $\%$)?

What rate of interest does a man get for his money when in discounting a bill due in $10 \, \text{months}$, he deducts $4 \%$ of the amount of the bill? (in $\%$)

If the banker's discount on a certain sum in $2$ years at a certain rate is $Rs. 150$ and the simple interest on the same sum in $3$ years is $Rs. 240$,find the sum (in $Rs.$) and the rate of interest (in $\%$).

$A$ shopkeeper allows a $20 \%$ discount on the marked price of his articles. Find the marked price of an article for which he charges $Rs. 740$. (in $Rs.$)