During 5 hours, a spider can catch 9 flies. How many flies would this spider catch in 30 hours if he would keep his efficiency? Give the rationale and then the answer.
Let's think step by step. 30 hours is 30 / 5 = 6 times more time. So the spider would be able to catch 6 * 9 = 54 flies.. The answer is: 54.

If Aang caught 7 fish, then Sokka caught 5 fish, and then Toph caught 12 fish, what is the average amount of fish that each person caught? Give the rationale and then the answer.
Let's think step by step. Aang, Sokka and Toph caught 7 fish + 5 fish + 12 fish = 24 fish. The average catch of fish per person is 24 fish / 3 people = 8 fish per person.. The answer is: 8.

Hally and her friends organized a high school reunion. To cover the cost of a late-night party that they planned for at the reunion, each attendee had to pay $100. After the party, Hally and her friends realized that the total expenses were $500 less than the total contributions. If there were 50 people at the party, how much money was used to pay for the party expenses? Give the rationale and then the answer.
Let's think step by step. The total planned cost for the party was 100 * 50 = $5000. The total expenses for the party are 5000 - 500 = $4500.. The answer is: 4500.