$A$ 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?

If $Rs. 10$ is allowed as true discount on a bill of $Rs. 110$ due at the end of a certain time,then the discount allowed on the same amount due at the end of double the time is (in $Rs.$)

While selling a shirt,a shopkeeper gives a discount of $7 \%$. If he gives a discount of $9 \%$,he earns $Rs. 15$ less in profit. The marked price of the shirt is (in $Rs.$):

The banker's gain on a bill due $1$ $year$ hence at $15 \%$ p.a. is $Rs.\, 9$. The true discount is (in $Rs.$)

$A$ watch dealer pays $10 \%$ customs duty on a watch which costs $Rs.\, 500$ abroad. He desires to make a profit of $20 \%$ after giving a discount of $25 \%$ to the buyer. The marked price should be (in $Rs.$)

If the simple interest on $Rs. 2000$ at $5\%$ $p.a.$ is equal to the true discount on $Rs. 2500$ for the same time and at the same rate,the time is (in $years$)