Ratio of CP and SP is 12:13, then the profit percent is?

Selling price of an article is $${7\over6}$$ of cost price. What is the profit percentage?

Rahul purchased 20 dozens of toys at the rate of Rs. 375 per dozen. He sold each one of them at the rate of Rs. 33. What was his percentage profit?

If a manufacturer gains 10 percent, wholesaler 15 percent and retailer 25 percent, then the production cost of an article, whose retail price is Rs. 1,265, is 

A shopkeeper sold his goods at half the list price and thus lost 20 %. If he had sold on the listed price, his gain percentage would be 

If Cost Price of 20 tables is equal to the Selling Price of 25 tables. Find the loss percentage.

Arun purchased 30 kg. of rice at the rate of Rs. 17.50 per kg. and another Rs. 30 kg. at a certain rate. He mixed the two and sold the entire quantity at the rate Rs. 18.60 per kg. and made 20% overall profit. At what price per kg. did he pruchase the lot of another 30 kg. rice?

From 2008 to 2009, the sales of a book decreased by 80%. If the sales in 2010 were the same as in 2008, by what percent did it increase from 2009 to 2010?