A trader offers a 10% discount on the marked price and provides 3 articles free for every 12 articles purchased, thereby earning a profit of 20%. Find the percentage by which the marked price is increased above the cost price, correct to two decimal places.

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?