The present worth of a sum due after a certain time is $Rs. 1024$ and the banker's gain is $Rs. 36$. The true discount is (in $Rs.$):

If the selling price is $Rs. 1680$ after getting a discount of $16 \%$ what was the marked price? (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 $Rs.$):

$A$ cloth merchant has announced a $25 \%$ rebate in prices. If one needs to have a rebate of $Rs. 40$,then how many metres of cloth costing $Rs. 32$ per metre should he purchase?

The banker's gain on a certain sum of money due for $9$ months at $4 \%$ $p.a.$ is $Rs. 2.25$. The sum is (in $Rs.$)

Ticket for an adult is $Rs. 1500$ and that of a child is $Rs. 800$. One child goes free with two adults. If a group has $25$ adults and $12$ children,what is the discount the group gets? (in $\%$)