Three weeks ago, there were 40 - 10 = 30 campers. The total number of campers from three to two weeks ago is 30 + 40 = 70. Hence, there were 150 - 70 = 80 campers last week.
The answer: 80
Reverse engineering the question: A camping site recorded a total of 150 campers for the past three weeks. Two weeks ago, there were 40 campers which was 10 more than the number of campers three weeks ago. How many campers were there last week?


Reasoning and answer: The second course cost Amelia $15 + $5 = $20. The dessert cost 25 / 100 * $20 = $5. That leaves Amelia with $60 - $15 - $20 - $5 = $20.
The answer: 20
What was the question?
Question: Amelia has $60 to spend on her dinner at a restaurant. The first course costs $15 and the second course $5 more. The cost of the dessert is 25% of the price of the second course. How much money will Amelia have left after buying all those meals?


Let X be the amount owned by James. The amount owned by Ali is X - $40. The total amount owned by both of them X + (X - $40) = $250. Combining like terms, we get X * 2 - $40 = $250. Adding $40 to both sides, we get X * 2 = $290. Dividing both sides by 2, we get X = $145.
The answer: 145
Reverse engineering the question: James and Ali together own $250. If you know that James owns $40 more than Ali, then calculate the amount owned by James.


Reasoning and answer: Let s be the amount of soda Carla drank and w be the amount of water she drank. We know that s + w = 54 and s = 3w - 6. Substituting the second equation into the first, we get 3w - 6 + w = 54. Combining like terms, we get 4w - 6 = 54. Adding 6 to both sides, we get 4w = 60. Dividing both sides by 4, we get w = 15.
The answer: 15
What was the question?
Question: Compared to the amount of water she drank, Carla drank three times as much soda minus 6 ounces. If she drank 54 ounces of liquid total, how much water did she drink?


First find the total cost of the two $8 cards: $8 / card * 2 cards = $16. Then subtract the cost of the cards Nicky gave away from the cost of the card he received to find his profit: $21 - $16 = $5.
The answer: 5
Reverse engineering the question: Nicky is trading baseball cards with Jill. If Nicky trades two cards worth $8 each for 1 card worth $21, how many dollars of profit does he make?


The number of people who took only wine is the difference between the number of people who took wine and those who took wine and soda which is 26 - 17 = 9 people. In the same manner, the number of people who took only soda is 22 - 17 = 5 people. Therefore the total number present is the sum of those who took wine only, those who took soda only and those who took both which is 9 + 5 + 17 = 31 people.
The answer: 31
Reverse engineering the question:
At a gathering, it was reported that 26 people took wine, 22 people took soda, and 17 people took both drinks. If each person could have taken one or more drinks regardless of what was reported, how many people altogether were at the gathering?