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 $\%$)

$A$ shopkeeper purchased $70$ $kg$ of potatoes for $Rs. 420$ and sold the whole lot at the rate of $Rs. 6.5$ per $kg$. What will be his gain percent?

$A$ bakery bakes cakes with the expectation that it will earn a profit of $40 \%$ by selling each cake at the marked price. During delivery to the showroom, $16 \%$ of the cakes were completely damaged and could not be sold. $24 \%$ of the cakes were slightly damaged and were sold at $80 \%$ of the cost price. The remaining $60 \%$ of the cakes were sold at the marked price. What is the percentage profit on the whole consignment (in $\%$)?

If $5 \%$ more is gained by selling an article for $Rs. 350$ than by selling it for $Rs. 340$,the cost price of the article is:

The cash difference between the selling prices of an article at a profit of $4 \%$ and $6 \%$ is $Rs. 3$. The ratio of the two selling prices is:

$A$ trader marked the selling price of an article at $10 \%$ above the cost price. At the time of selling,he allows a certain discount and suffers a loss of $1 \%$. He allowed a discount of $\%$: