If a shopkeeper wants to give a $20 \%$ discount on a toy, he has to sell it for $Rs. 300$. If he sells it at $Rs. 405$, then his gain percent is: (in $\%$)

$60 \%$ of the cost price of an article is equal to $50 \%$ of its selling price. Then the percentage of profit or loss on the cost price is

$A$ man purchased some eggs at $3$ for $Rs. 5$ and sold them at $5$ for $Rs. 12$. Thus,he gained $Rs. 143$ in all. The number of eggs he bought is:

$A$ 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 $Rs.$)

Harkesh bought a certain quantity of tomato at the rate of $Rs. 1500$ per quintal. $10 \%$ of the tomato was spoiled. At what price in $Rs.$ per quintal should he sell the remaining to gain $20 \%$ of his outlay?

$A$ trader marks his goods $40 \%$ above the cost price and allows a discount of $25 \%$. The profit he makes,is in $\%$: