Answer the following question.
The capacity of Karson's home library is 400 books. If he currently has 120 books, how many more books does he have to buy to make his library 90% full?
Step-by-step reasoning process: When 90% full, Karson's library holds 90 / 100 * 400 = 360 books. If he has 120 books in the library now, he needs to buy 360 - 120 = 240 books to make his library 90% full.
The answer is 240.

Answer the following question.
James trains for the Olympics. He trains twice a day for 4 hours each time for all but 2 days per week. How many hours does he train a year?
Step-by-step reasoning process: He trains 4 * 2 = 8 hours per day. He trains 7 - 2 = 5 days. So he trains 8 * 5 = 40 hour per week. That means he trains 40 * 52 = $2080.
The answer is 2080.

Answer the following question.
Beth has 72 marbles of three colors. Each color has the same amount of marbles. If Beth loses 5 red, twice as many blue, and three times as many yellow ones than red ones, how many marbles does she have left?
Step-by-step reasoning process: Beth has 72 / 3 = 24 marbles of each color. Beth has 24 - 5 = 19 red ones left. Beth lost 5 * 2 = 10 blue ones. Beth has 24 - 10 = 14 blue ones left. Beth lost 5 * 3 = 15 yellow ones. Beth has 24 - 15 = 9 yellow ones left. She has a total of 19 + 14 + 9 = 42 marbles left.
The answer is 42.

Answer the following question.
Martin has 18 goldfish. Each week 5 goldfish die. Martin purchases 3 new goldfish every week. How many goldfish will Martin have in 7 weeks?
Step-by-step reasoning process: In 7 weeks 5 * 7 = 35 goldfish die. In 7 weeks, Martin purchases 3 * 7 = 21 goldfish. In 7 weeks, Martin will have 18 - 35 + 21 = 4 goldfish.
The answer is 4.