The first movie was 60 + 30 = 90 minutes long since an hour has 60 minutes. The second movie was 90 + 30 = 120 minutes long. It took them a total of 90 + 120 = 210 minutes to watch the two movies. It took them 10 x 2 = 20 minutes to cook the fries. Thus, it took them a total of 10 + 20 = 30 minutes to cook. So, they spent 210 + 30 = 240 minutes watching the movies and cooking. In hours, this is equal to 240 / 60 = 4 hours.
The answer: 4
Reverse engineering the question: Joseph and his friends watched two movies in his house. The first movie is 1 hour and 30 minutes long while the second movie is 30 minutes longer than the first. Before the movies, they spent 10 minutes making popcorn and twice as long making fries. How long, in hours, did it take Joseph and his friends to cook and watch the movies?


Reasoning and answer: There are 4 * 7 = 28 days in those 4 weeks. That means he takes 28 / 2 = 14 showers. So he takes a total of 14 * 10 = 140 minutes of showers. So he uses 2 * 140 = 280 gallons of water.
The answer: 280
What was the question?
Question: John takes a 10-minute shower every other day for 4 weeks. If his shower uses 2 gallons of water per minute. How much water does he use in those 4 weeks?


The weekly salary of Agnes is $15 x 8 = $120. So in a month, Agnes earns $120 x 4 = $480. Therefore, Mila needs to work for $480 / $10 = 48 hours to earn as much as Agnes's monthly earnings.
The answer: 48
Reverse engineering the question: There are two babysitters named Mila and Agnes. Mila makes $10 an hour while Agnes makes $15 an hour. Agnes works 8 hours each week. How many hours does Mila need to work to earn as much as Agnes in a month?


Reasoning and answer: If they are to save every month for three years to reach the target amount, and each year has 12 months, they'll save for 12 * 3 = 36 months. If the house's downpayment is $108000, the total amount they both save per month is $108000 / 36 = $3000 every month. Since they share the monthly savings, each person will pay $3000 / 2 =  = $1500.
The answer: 1500
What was the question?
Question: It will take Richard and Sarah 3 years to save enough for a down payment on a house at their current rates. If the house's downpayment is $108000, calculate the amount each person saves per month if they share the monthly savings.


Anne is 2 times as tall as her sister hence 2 * (her sister's height) = 80cm. Her sister's height = 80cm / 2 = 40cm. Bella is 3 times as tall as Anne hence Bella's height is 3 * 80 cm = 240 cm. The height difference between Bella and Anne's sister = 240 - 40 = 200cm.
The answer: 200
Reverse engineering the question: Anne is 2 times as tall as her sister while Bella is 3 times as tall as Anne. If Anne is 80cm tall, what is the height difference between Bella and Anne's sister?


The school needs to buy 30 - 12 = 18 robes. So the school will spend 18 x $2 = $36.
The answer: 36
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 school choir needs robes for each of its 30 singers. Currently, the school has only 12 robes so they decided to buy the rest. If each robe costs $2, how much will the school spend?