$A$ $20 \%$ discount is offered on an item. By applying a promo code,the customer wins $30 \%$ cash back. What is the effective discount? (in $\%$)

If $Rs. 21$ is the true discount on $Rs. 371$ for a certain time,what is the true discount on the same amount for double that time,the rate being the same in both the cases? (in $Rs.$)

$A$ shopkeeper gives two successive discounts of $7 \%$ each on the marked price of $Rs.\, 20,000$ of an article. The selling price of the article is (in $Rs.$):

If two successive discounts of $20 \%$ and $30 \%$ are given,what is the net discount (in $\%$) ?

$A$ bill which is due at the end of $4 \text{ years}$ is now worth $Rs. 575$,but if it is due in $2 \frac{1}{2} \text{ years}$,it would now be worth $Rs. 620$. The sum of the bill is (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 $Rs.$)