By selling $25$ $metres$ of cloth,a trader gains the selling price of $5$ $metres$ of cloth. The gain of the trader in $\%$ is:

$A$ wholesaler had $200$ dozens of mangoes. He sold some of these mangoes at $20 \%$ profit and the rest at $10 \%$ profit,so that he made $13 \%$ profit on selling all the mangoes. How many mangoes (in dozens) did he sell at $20 \%$ profit?

$A$ man purchased $120$ reams of paper at $Rs. 80$ per ream. He spent $Rs. 280$ on transportation,paid octroi at the rate of $40$ paise per ream,and paid $Rs. 72$ to a porter. In order to gain $8\%$ profit,he must sell each ream of paper for (in $Rs.$):

An $Ox$ and a carriage together cost $Rs. 8000$. The ox is sold at a profit of $10\%$ and the carriage is sold at a loss of $10\%$. If the total profit made is $2.5\%$,then what is the cost price of the ox? (in $Rs.$)

$A$ shopkeeper bought $30\, Kg$ of wheat at the rate of $Rs.\, 45$ per $Kg$. He sold $40\%$ of the total quantity at the rate of $Rs.\, 50$ per $Kg$. Approximately,at what price per $Kg$ should he sell the remaining quantity to make $25\%$ overall profit? (in $Rs.$)

$A$ shopkeeper sold an item at $10 \%$ loss after giving a discount equal to half the marked price. The cost price of the item is ......... of the marked price.