If a shopkeeper bought 70 kg of potatoes for Rs 420 and sold the entire purchase at the rate of 6.50 per kg, what was his profit percentage?

If the cost of production of an article is 2/5 of its marked retail price, If it is sold at 10 % discount then what will be profit ? 

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:

An article was sold for Rs.4000. Had a discount of 10% was being offered, the profit would have been 20%. The cost price of the article was:

If a man were to sell his chair for Rs. 720, he would loss 25 %. To gain 25% he should sell it for__

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?

Ranveer bought a computer paying 25% less than the list price and sold it to his neighbour at a 40% profit on his purchase cost. The profit percentage earned by Ranveer on the list price of the computer is:

Cost of 8 pencils, 5 pens and 3 erasers is Rs.111. Cost of 9 pencils, 6 pens and 5 erasers is Rs.130. Cost of 16 pencils, 11 pens and 3 erases is Rs. 221 What is the Cost (in Rs) of 39 pencil , 26 pens and 13 erasers ?