An article is sold for Rs. 500 resulting in a certain loss. If this article is sold for Rs. 700, the trader gains three times the initial loss. Find the cost price of the 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?