If 20% profit is on cost price,what is profit percentage on selling price?

A sold his pen at a profit of ₹13. He calculated the profit percentage on selling price and found it to be 20%. The cost price (in ₹) of the pen is:

Selling price of an article is (8)/(7) of cost price. What is the profit percentage ?

In a certain store, the profit is 320% of the cost. If the cost increases by 25% but the selling price remains constant, approximately what percentage of the selling price is the profit?

For an article the profit is 190% of the cost price. If the cost price increases by 10% but the selling price remains same, then profit is what per- centage of selling price (ap-proximately) ?

If the profit is 20%, then what will be the ratio of cost price to selling price respectively?

If the profit on sale price be 20%, the percentage of profit on cost price is