His entire purchase cost $20 - $4 = $16. The chocolate bars cost 5 * $2 = $10. The bags of chips cost a total of $16 - $10 = $6. Each bag of chips cost $6 / 2 = $3.
The answer: 3
Reverse engineering the question: Frank goes to the store to buy some food. He buys 5 chocolate bars and 2 bags of chips. He hands the cashier $20 and gets $4 back as change. If the chocolate bars each cost $2, how much did each bag of chips cost?


Reasoning and answer: The store owner ordered a total of 20 + 30 = 50 cases. This is equal to 50 x 20 = 1000 bottles of soda.
The answer: 1000
What was the question?
Question: A store owner ordered 20 cases of bottles of soda in April and 30 cases in May. There are 20 bottles per case. How many bottles of soda did the store owner order in April and May?


Burning a candle for 1 hour lasts her 8 nights so if she burns for 2 hours it will last her 8 / 2 = 4 nights. 1 candle now lasts 4 nights and she needs enough for 24 nights so she needs 24 / 4 = 6 candles.
The answer: 6
Reverse engineering the question: Carmen burns a candle for 1 hour every night. A candle will last her 8 nights. If she burns the candle for 2 hours a night, how many candles will she use over 24 nights?


Reasoning and answer: Let x represent the number of passes thrown to the left side of the field. Right:2x. Center:x + 2. Total:x + 2x + x + 2 = 50. 4x + 2 = 50. 4x = 48. x = 12 passes.
The answer: 12
What was the question?
Question: A quarterback throws 50 passes in one game. He throws twice as many passes to the right of the field than he does to the left of the field. He throws 2 more passes to the center of the field than he did to the left. How many passes did he throw to the left side of the field?


8 x 2 = 16 are blue pens. 16 + 10 = 26 are black pens. 8 - 2 = 6 are red pens. Therefore, there are 16 + 26 + 6 = 48 pens in all in Sam's collection.
The answer: 48
Reverse engineering the question: In Sam's collection, there are ten more black pens than blue pens and twice as many blue pens as pencils. There are also eight pencils and two fewer red pens than pencils. How many pens in all are there in Sam's collection?


The second rocket goes 500 * 2 = 1000 feet. So the total height is 500 + 1000 = 1500 feet.
The answer: 1500
Reverse engineering the question:
John builds a model rocket that can travel 500 ft in the air. He builds a second rocket that can travel twice as high. What is the combined height of the two rockets?