150 रुपये अंकित मूल्य वाले एक छाते को 138 रुपये में बेचा जाता है। छूट की दर कितनी है?

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?