Keanu's motorcycle can store 8 liters of gasoline. If his destination is 280 miles away and his motorcycle consumes 8 liters of gasoline per 40 miles, how many times does Keanu have to refill his motorcycle with gasoline if he will make a round trip? Give the rationale and then the answer.
Let's think step by step. The total number of miles for a round trip is 280 x 2 = 560. Therefore, he needs to refill his motorcycle 560 / 40 = 14 times.. The answer is: 14.

John decides to take up illustration. He draws and colors 10 pictures. It takes him 2 hours to draw each picture and 30% less time to color each picture. How long does he spend on all the pictures? Give the rationale and then the answer.
Let's think step by step. The coloring takes 2 * .3 = .6 hours less than the drawing. So it takes 2 - .6 = 1.4 hours per picture. So it takes him 2 + 1.4 = 3.4 hours per picture. That means it takes 3.4 * 10 = 34 hours.. The answer is: 34.

Wendy went to the dentist for a cleaning, two fillings, and a tooth extraction. The dentist charges $70 for a cleaning and $120 for a filling. Wendy’s dentist bill was five times the cost of a filling. What did Wendy pay for the tooth extraction? Give the rationale and then the answer.
Let's think step by step. Wendy’s dentist bill was 5 * $120 = $600. She got two fillings at a cost of 2 * $120 = $240. Thus, Wendy paid $600 - $240 - $70 = $290 for the tooth extraction.. The answer is: 290.