Cost of 36 pens and 42 Pencils is Rs 460. What is the cost of 18 pens and 21 pencils?

If the selling price of a product is multiplied by 2, the resulting profit is 6 times the original profit. What is the original profit percentage?

A cow was sold at 8% profit. If it were bought at 20% less and sold at 40% profit, then the owner would gain ₹ 640 more. Find the initial cost price of the cow.

A scientist mixes 10% water in his solution but he is not content with it so he again mixes 10% more water in the previous mixture. What is the profit percentage of the scientist if he sells it at cost price:

A trader had 16 quintals of wheat. He sold a part of it at 17% profit and the rest at 27% profit, so that he made a total profit of 21%. How much wheat did he sell at 27 % profit? 

If a man purchase 11 articles for Rs.10 and sold all the articles at the rate of 10 for Rs.11, the profit percentage will be.

If a vendor sells apples at Rs 170 per kg he suffers 15 % loss. If he sells at Rs 230 per kg, then what is his profit percentage?