[Question]: A trolley driver picked up 10 people on his 1st stop. On the next stop, 3 people got off and twice as many people from the 1st stop got on. On the third stop, 18 people got off and 2 got on. How many people are currently on the trolley?
[Answer]: Between the trolley driver and his first 10 customers, there are 1 + 10 = 11 people are currently on the trolley. On his first stop, 10 people go on and twice as many people got on at the second stop so 10 * 2 = 20 people got on at the second stop. So at the second stop he had 11 people on board, 3 got off and 20 got on so he now has 11 - 3 + 20 = 28 people. At his third stop 18 people got off and 2 got on so in total there are 28 - 18 + 2 = 12 people on the trolley.
So the answer is 12.

[Question]: Abby is building 2 raised beds to grow vegetables. The beds are both 8 feet long, 4 feet wide and 1 foot high. Each bag of soil has 4 cubic feet. How many bags of soil will she need?
[Answer]: One garden bed measures 8ft long, 4ft wide and 1ft high so to find the cubic feet needed, 8 * 4 * 1 = 32 cubic feet of soil needed. Both beds are the same size so she needs 2 * 32 = 64 cubic feet of soil. Every bag has 4 cubic feet of soil and she needs 64 cubic feet so 64 / 4 = 16 bags needed.
So the answer is 16.

[Question]: What is the average age of the 1st and 5th fastest dogs if the 1st fastest dog is 10 years old, the 2nd fastest dog is 2 years younger than the first fastest dog, the 3rd fastest dog is 4 years older than the 2nd fastest dog, the 4th fastest dog is half the age of the 3rd fastest dog, and the 5th fastest dog is 20 years older than the 4th fastest dog?
[Answer]:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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If the 1st fastest dog is 10 years old, and the 2nd fastest dog is 2 years younger than the first fastest dog, the 2nd fastest dog is 10 - 2 = 8 years old. The 3rd fastest dog being 4 years older than the 2nd fastest dog, is 8 + 4 = 12 years old. The 4th fastest dog is half the age of the 3rd fastest dog, meaning the 4th fastest dog is 1 / 2 * 12 = 6 years old. The 5th fastest dog is 20 years older than the 4th fastest dog, meaning the 5th fastest dog is 6 + 20 = 26 years old. The total age of the 1st and 5th fastest dogs is 26 + 10 = 36 years. The average age of the 1st and 5th fastest dogs is 36 / 2 = 18 years old.
So the answer is 18.