The large paintings have used 3 * 3 = 9 ounces. The small paintings have used 2 * 4 = 8 ounces. In total, all the paintings have used 9  + 8 = 17 ounces.
The answer: 17
Reverse engineering the question: An artist uses 3 ounces of paint for every large canvas they cover, and 2 ounces of paint for every small canvas they cover.  They have completed 3 large paintings and 4 small paintings.  How many ounces of paint have they used?


Reasoning and answer: The three friends had meals worth 10 * 3 = 30 dollars. If they paid for the meals only, they would have remained with 45 - 30 = 15 dollars. Dividing the remaining amount by the number of ice cream scoops gives 15 / 3 = 5 dollars. Each scoop of ice cream cost 5 dollars.
The answer: 5
What was the question?
Question: Elisa and her two friends went out to dinner. Each of them ordered a meal worth $10. Afterwards, they each had a scoop of the same kind of ice cream. If the $45 Elisa had was enough to pay for everything, what was the cost of a scoop of ice cream?


Kevin begins the day with 15 phones and repairs 3 by the afternoon, so Kevin still has to repair 15 - 3 = 12 phones. A client drops off 6 additional phones that require fixing, increasing the total to 12 + 6 = 18 phones. If Kevin's coworker helps Kevin fix half of the phones, then each person needs to fix 18 / 2 = 9 phones.
The answer: 9
Reverse engineering the question: Kevin repairs phones at his job. At the beginning of the day, Kevin has 15 phones that need to be repaired. By the afternoon, Kevin has successfully repaired 3 of the 15 phones and a client has dropped off 6 more phones that need fixing. If a coworker of Kevin's offers to help him and fix half of the damaged phones, how many phones will each person need to repair?


Reasoning and answer: The down payment Rita made was 120 / 2 = 60 dollars. The balance was therefore 120 - 60 = 60 dollars. To pay off the balance within 10 days, Rita must make payments of 60 / 10 = 6 dollars per day.
The answer: 6
What was the question?
Question: Rita put a $120 elliptical machine on layaway at her local sports good store. After making a down payment equal to half the cost of the machine, she completely forgot about it. Sometime before the pick-up date, a store employee called offered to waive all layaway fees and taxes on the condition that Rita paid the balance within 10 days. What is the daily minimum amount, in dollars, that Rita must pay to own the elliptical machine?


In 2 years there are 365 * 2 = 730 days. So he has learned 730 * 10 = 7300 words. He knew 1 / .5 = 2 times that number of words before the book. So he knew 7300 * 2 = 14600 words before.
The answer: 14600
Reverse engineering the question: Tim buys a book of esoteric words. He learns 10 words from it a day. In 2 years the book has increased the number of words he knows by 50%. How many words did he know originally?


In the second week, 15 x 3 = 45 bags of chips were sold. So there was a total of 45 + 15 = 60 bags of chips sold on the first and second week. Thus, a total of 100 - 60 = 40 bags of chips were sold on the third and fourth week. Therefore, 40 / 2 = 20 bags of chips were each sold on the third and fourth week.
The answer: 20
Reverse engineering the question:

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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A convenience store sold 100 bags of chips in a month. In the first week, 15 bags of chips were sold. In the second week, thrice as many bags of chips were sold. There was an equal number of chips sold in the third and fourth week. How many chips was each sold in the third and fourth week?