A shopkeeper buys two articles at the same cost price. He sells the first article at a profit of 25% and the second article at a loss of 20%. If the selling price of the first article is ₹180 more than that of the second article, then find the cost price of each article.

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?