A person bought two articles for ₹1,800 and sold the first at 15% profit and the second at 30% profit. If he sold the first at 30% profit and the second at 15% profit, he would get ₹3 more. The difference in the cost price of the two articles was:

A company considers hiring an extra machine for $150 per day to produce additional units. If the additional throughput contribution generated from producing these units on the machine is $390, by how much will total profit increase?

If the cost price of an article is 85 times its selling price, what is the loss percentage?