While selling an article for Rs. 8,442, a person suffered a loss of 30%. At what price should he have sold the article to earn a profit of 20%?

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?