$A$ shopkeeper allows a discount of $12.5 \%$ on the marked price of a certain article and makes a profit of $20 \%$. If the article costs the shopkeeper $Rs. 210$,then the marked price of the article will be (in $Rs.$)

$A$ 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 $\%$:

$A$ man bought nine pens for a rupee. How many pens should he sell for a rupee to gain $50 \%$?

The cost of an article including the sales tax is $Rs. 616$. The rate of sales tax is $10 \%$. If the shopkeeper has made a profit of $12 \%$,then the cost price of the article is 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 $Rs.$)

$A$ shopkeeper purchased $245$ pieces of an article at $Rs. 30$ per piece. He spent $Rs. 980$ on transport and $Rs. 1470$ on packing the articles. He sold the articles at the rate of $Rs. 50$ per piece. What is the percent profit earned?