Ofelia saves $10 x 2 = $20 in February. She will save $20x 2 = $40 in March. She will save $40 x 2 = $80 in April. Thus, she will save $80 x 2 = $160 in May.
The answer: 160
Reverse engineering the question: Ofelia joined a saving challenge wherein she has to save twice the amount she saved from the previous month. In January, she saved $10. How much is she going to save in May?


Reasoning and answer: He got 300 * 2 = $600. So he got 600 / 20 = 30 bills.
The answer: 30
What was the question?
Question: Tye goes to two different banks and withdraws $300 from each bank. If he got it all in 20 dollar bills how many bills did he get?


4 hours is 4 * 60 = 240 minutes. If the doubling time is 20 minutes, then after 240 minutes, the number of bacteria would have doubled 240 / 20 = 12 times. Thus, starting with only 1 bacterial cell, after 4 hours, there will be 1 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 = 4,096 bacterial cells.
The answer: 4096
Reverse engineering the question: Under standard growth conditions, the bacterial strain, E.coli, has a doubling time of 20 minutes.  If 1 single bacterial cell is used to start a culture grown under standard growth conditions, how many bacterial cells will there be after the culture is grown for 4 hours?


Reasoning and answer: 15 bottles of cola is a cost of 15 * 3 = $45. 12 bottles of juice make up to 12 * 1.5 = $18. As each of the 25 sold water bottles was $1, the shop made a total of 45 + 18 + 25 = $88.
The answer: 88
What was the question?
Question: In a certain country store, there are three kinds of bottled drinks. A cola, which costs $3, a juice for $1.5, and water for $1 per bottle. One day the store was able to sell 15 bottles of cola, 25 bottles of water, and 12 bottles of juice. How much did the shop earn?


For the tuna Barbara needed to pay 5 * 2 = $10. For the four bottles of water, she needed to pay 4 * 1.5 = $6. On different goods Barbara spend 56 - 10 - 6 = $40.
The answer: 40
Reverse engineering the question: Barbara went shopping in a supermarket. She bought 5 packs of tuna for $2 each and 4 bottles of water for $1.5 each. In total, she paid $56 for her shopping. How much did Barbara spend on different than the mentioned goods?


The builder purchased 7 boxes * 11 bolts = 77 bolts. He used 77 bolts - 3 left over = 74 bolts for the project. The builder purchased 3 boxes * 15 nuts = 45 nuts. He used 45 nuts - 6 left over = 39 nuts for the project. Total for the project he used 74 bolts + 39 nuts = 113 nuts and bolts.
The answer: 113
Reverse engineering the question:
For a project, a builder purchased 7 boxes of bolts with each box containing 11 bolts. He purchased 3 boxes of nuts with each box containing 15 nuts. He ended up finishing the project 6 days early and with 3 bolts and 6 nuts left over. How many bolts and nuts did he use for the project?