$A$ vendor bought toffees at $6$ for a rupee. How many for a rupee must he sell to gain $20 \%$?

An article is marked for sale at $Rs. 504$. The shopkeeper gives a discount of $5\%$ on the marked price and still earns a profit of $20\%$. What is the cost price of the article? (in $Rs.$)

Rita buys an article for $Rs. 9600$. She sold it at $12\%$ loss and gets some money,and from that money,she again buys an article and this time she gets $12\%$ profit. What was the profit or loss she got from this transaction in $Rs.$?

The selling price of a chair is $Rs. 1386$. If the loss percentage is $23\%$,what is the cost price (in $Rs.$) of the chair?

$A$ shopkeeper sold a $TV$ set for $Rs. 17940$ with a discount of $8 \%$ and earned a profit of $19.6 \%$. What would have been the percentage of profit earned if no discount was offered (in $\%$)?

The marked price of a bed is $Rs. 2400$. The shopkeeper gives successive discounts of $10 \%$ and $X \%$ to the customer. If the customer pays $Rs. 1836$ for the bed,then find the value of $X$ in $\%$.