If the selling price is doubled,the profit triples. Find the profit percent.

While selling a watch,a shopkeeper gives a discount of $15 \%$. If he gives a discount of $20 \%$,he earns $Rs. 51$ less as profit. What is the original price of the watch? (in $Rs$)

Hundred oranges are bought at the rate of $Rs. 350$ and sold at the rate of $Rs. 48$ per dozen. The percentage of profit or loss is:

Meenal purchased a car for $Rs. 2,50,000$ and sold it for $Rs. 3,48,000$. What is the percent profit she made on the car?

Kamal has some apples. He sold $40\%$ more than he ate. If he sold $70$ apples,how many did he eat?

An article is listed at $Rs. 65$. $A$ customer bought this article for $Rs. 56.16$ and received two successive discounts,of which one is $10 \%$. Find the other discount in this discount scheme offered by the shopkeeper (in $\%$).