A shopkeeper sold an article for Rs. 180 by making a profit of 20%. If the shopkeeper offered a discount of Rs. 30 on the marked price, then what is the markup percentage?

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?