The marked price of an article is twice the cost price. For a gain of $30 \%$,what should be the discount percentage?

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 $Rs.$)

If the compound interest on a certain sum of money for $2 \text{ years}$ at $4 \%$ per annum is $Rs. 45.90$,the true discount on the same amount of money due $2 \text{ years}$ hence at $4 \%$ per annum simple interest is (in $Rs.$):

If the true discount on $Rs. 249$ at $5\%$ simple interest $(S.I.)$ is $Rs. 9$,when is the sum due? (in months)

The price of an article is cut by $42 \%$. To restore it to its original value,the new price must be increased by (in $\%$):

$A$ 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 $Rs.$):