Anil bought an item with $12 \frac{1}{2} \%$ discount on the labelled price. He sold the item with $17 \frac{1}{2} \%$ profit on the labelled price. What was his percent profit on the price he bought?

The cost price of $6$ pens is equal to the selling price of $4$ pens. Find the profit percent. (in $\%$)

$A$ shopkeeper sold decks at $Rs. 166$ each after giving $17\%$ discount on the labelled price. Had he not given the discount,he would have earned a profit of $25\%$ on the cost price. What was the cost price of each deck? (in $Rs.$)

Two-thirds of a consignment was sold at a profit of $5 \%$ and the remainder at a loss of $2 \%$. If the total profit was $Rs. 400$,what was the total value of the consignment in $Rs.$?

$A$ trader purchases a wrist watch and a pendulum for $Rs. 390$. He sells them making a profit of $10 \%$ on the watch and $15 \%$ on the pendulum. He earns a total profit of $Rs. 51.50$. The difference between the original prices of the pendulum and the watch is equal to? (in $Rs.$)

$A$ merchant buys $4000 \, kg$ of wheat,one-fifth of which he sells at a gain of $5 \%$,one-fourth at a gain of $10 \%$,one-half at a gain of $12 \%$,and the remainder at a gain of $16 \%$. If he had sold the whole at a gain of $11 \%$,he would have made $Rs. 72.80$ more. What was the cost price of the crop per $kg$? (in $Rs.$)