Q: Miss Molly surveyed her class of 30 students about their favorite color. Half of the class answered green, one-third of the girls answered pink, and the rest of the class answered yellow. If there are 18 girls in the class, how many students like yellow best?
A: 30 / 2 = 15 students answered green. 18 / 3 = 6 girls answered pink. So, 15 + 6 = 21 students answered either green or pink. Therefore, 30 - 21 = 9 answered yellow. The answer is 9.
Question: John needs to replace his shoes so he decides to buy a $150 pair of Nikes and a $120 pair of work boots. Tax is 10%. How much did he pay for everything?
Answer: The shoes cost $150 + $120 = $270. The tax was $270 * .1 = $27. So the total cost was $270 + $27 = $297. The answer is 297.
[Question]Tom swims for 2 hours at a speed of 2 miles per hour. He then runs for half the time at 4 times the speed. How many miles did he cover?
[Answer]He swam 2 * 2 = 4 miles. He ran for 2 / 2 = 1 hour. His running speed was 2 * 4 = 8 mph. So he ran 8 * 1 = 8 miles. So his total distance was 8 + 4 = 12 miles. The answer is 12.
Q: It takes David 10 minutes to wash 4 windows. David's house has 64 windows. How many minutes will it take David to wash all of the windows?
A: It takes 10 minutes to wash 4 windows and he has 64 windows so that breaks down to 64 / 4 = 16 units. It takes 10 minutes to wash a unit of windows and he has 16 units so 10 * 16 = 160 minutes. The answer is 160.
Question: By the time Anne is two times as old as Emile, Emile will be six times as old as Maude. If Maude will be 8 years old, how old will Anne be?
Answer: If Maude's age is 8 by the time Anne's age is four times Emile's age, Emile will be six times as old as Maude, which totals 6 * 8 = 48 years. If Emile's age is 48 years old by the time Anne's age is twice her number, Anne will be 2 * 48 = 96 years. The answer is 96.
Q: Lorenzo put three full cans of thumbtacks into his pocket and went off to work at the corkboard factory. It was Lorenzo's job, as head of quality control, to test every cork board for its ability to hold thumbtacks. He placed one thumbtack from each of the three cans of thumbtacks into every board tested. At the end of the day, he had tested 120 boards and had 30 tacks remaining in each of the three cans. What was the total combined number of thumbtacks from the three full cans?
A:

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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At the end of the day, he had tested 120 boards, each with three tacks, for a total of 3 * 120 = 360 tacks. He had 30 tacks remaining in each of the three cans, for an additional 3 * 30 = 90 thumbs tacks. Therefore, the original total combined number of thumbtacks in the three full cans of thumbtacks was 360 + 90 = 450 thumbtacks. The answer is 450.