Question: Charles bought 20 papers to draw. Today Charles drew 6 pictures. Yesterday he drew 6 pictures before going to work and some pictures when he came back. How many pictures did Charles draw when he came back from work knowing that he has 2 papers left?
Answer: Step-by-step reasoning process: Charles drew 6 + 6 = 12 pictures. He has 20 - 12 = 8 papers left. So Charles drew when he came back from work 8 - 2 = 6 pictures.
So the answer is 6.

Question: Casey takes 6 hours to complete a marathon race, while Zendaya takes 1/3 times longer to cover the same distance. What is the average time the two take to complete to race?
Answer: Step-by-step reasoning process: Zendaya takes 1 / 3 * 6 hours = 2 hours longer to complete the marathon. To complete the marathon, Zendaya takes 6 hours + 2 hours = 8 hours. The combined time the two take to complete the marathon is 8 hours + 6 hours = 14 hours. The average number of hours Casey and Zendaya take to complete the marathon is 14 hours / 2 people = 7 hours / person.
So the answer is 7.

Question: Gerald had 20 toy cars. He donated 1/4 of his toy cars to an orphanage. How many toy cars does Gerald have left?
Answer: Step-by-step reasoning process: Gerald gave away 20 x 1 / 4 = 5 of his toy cars. Therefore, he is left with 20 - 5 = 15 toy cars.
So the answer is 15.

Question: John has a very inefficient toilet that uses 5 gallons of water per flush and his household flushed 15 times per day. He replaced it with a toilet that uses 80% less water per flush. How much water did John save in June?
Answer:
Step-by-step reasoning process: He used to use 5 * 15 = 75 gallons of water per day. This means he used 75 * 30 = 2250 gallons a month. His new toilet uses 5 * .8 = 4 gallons less water per flush. So, it only uses 5 - 4 = 1 gallon per flush. That means he uses 1 * 15 = 15 gallons per day. All in all, it accounts for a total usage of 15 * 30 = 450 gallons. So, he saved 2250 - 450 = 1800 gallons per month.
So the answer is 1800.