To purchase a book for each student, Sally needs: 30 x $12 = $360. She thus needs to pay $360 - $320 = $40 out of pocket.
The answer: 40
Reverse engineering the question: Sally teaches elementary school and is given $320 to spend on books for her students. A reading book costs $12 and there are 30 students in her class. Unfortunately, if the money she is given by the school to pay for books is not sufficient, she will need to pay the rest out of pocket. How much money does Sally need to pay out of pocket, to buy every student a reading book?
Reasoning and answer: First find the total number of guppies the betta fish need: 5 fish * 7 guppies / fish = 35 guppies. Then add the number of guppies the eel needs to find the total number needed: 35 guppies + 20 guppies = 55 guppies.
The answer: 55
What was the question?
Question: Jason has a moray eel that eats 20 guppies a day and 5 betta fish who each eat 7 guppies a day. How many guppies per day does she need to buy?
She sleeps 7 * 5 = 35 hours on weekdays. She sleeps 8 * 2 = 16 hours on weekends. 35 + 16 = 51 hours is the amount of time she sleeps in a week.
The answer: 51
Reverse engineering the question: Janna sleeps 7 hours each day during weekdays and 8 hours each day during weekends. How many hours does she sleep in a week?
Reasoning and answer: For 5 apples, Mary will pay 5 * 1 = 5 dollars. For 3 oranges, she will pay 3 * 2 = 6 dollars. For 2 bananas, she will pay 2 * 3 = 6 dollars. She bought 5 + 3 + 2 = 10 fruits. For 10 fruits, Mary gets a discount of 10 / 5 = 2 dollars. In total, the bill is 5 + 6 + 6 = 17 dollars. Subtracting the discount offered by the stores, Mary will pay 17 - 2 = 15 dollars.
The answer: 15
What was the question?
Question: Mary went to the store to buy fruit. Apples cost $1, oranges cost $2, and bananas cost $3. For every 5 fruits that customers buy, the store offers a $1 discount. Mary buys 5 apples, 3 oranges, and 2 bananas. How much will she pay?
If he melts them down, five quarters equals $100 because 1 / (1 / 5) = 5. If he spends those five quarters they are worth $1.25 because 5 x .25 = 1.25. They are worth 80 times more melted down because 100 / 1.25 = 80.
The answer: 80
Reverse engineering the question: Carlos has some gold quarters. If he spends them in a store, they are worth the regular amount. If he melts them down, he can get $100 per ounce. Each quarter weighs 1/5 of an ounce. How many times more money would he get from melting them down instead of spending them in a store?
The total number of songs downloaded is 10 songs + 15 songs + 3 songs = 28 songs. The total size of the songs is 28 songs x 5MB / song = 140 MB.
The answer: 140
Reverse engineering the question:
Kira wants some new music on her phone. She downloads 10 songs in the morning. Later on that day, she finds 15 more songs she likes so she downloads them, and at night a friend of hers recommends 3 more songs she also downloads. Knowing that each song has a size of 5 MB, how much memory space in MB will the new songs occupy?