Question: John buys a heating pad for $30. He uses it 3 times a week for 2 weeks. How much does he spend on each use?
Answer with step-by-step thinking: He uses it 3 * 2 = 6 times. So he pays 30 / 6 = $5.
So the answer is 5.

Question: John commissions an artist to make him a 9 by 13 drawing. A black and white drawing that size would cost $160. He wants a color drawing so that is 50% more expensive. How much did he pay?
Answer with step-by-step thinking: The extra cost for coloring is 160 * .5 = $80. So the total cost was 160 + 80 = $240.
So the answer is 240.

Question: Maria collects stamps and wants to enlarge her collection. She has collected 40 stamps so far and plans to have 20% more. How many stamps in total does Maria want to collect?
Answer with step-by-step thinking:
Maria plans on having 40 * 20 / 100 = 8 more stamps in her collection. This means she wants to have 40 + 8 = 48 stamps.
So the answer is 48.