The binders cost 3 binders * $2 / binder = $6. The notebooks cost 6 notebooks * $1 / notebook = $6. The amount of Lea’s purchases is: $16 + $6 + $6 = $28.
The answer: 28
Reverse engineering the question: Léa bought one book for $16, three binders for $2 and six notebooks for $1. Calculate the total cost of her purchases.


Reasoning and answer: She earned $42.5 on average per week because 425 / 10 = 42.5. She earned $22.5 each week from extra chores because 42.5 - 20 = 22.5. She did 15 extra chores a week because 22.5 / 1.5 = 15.
The answer: 15
What was the question?
Question: Carol gets a fixed $20 allowance each week. She can also earn $1.5 more dollars each week if she does extra chores. At the end of 10 weeks, she has 425 dollars. How many extra chores did she average each week?


On the first day Chandra saw 2 monsters and on day 2 she saw twice that amount, 2 x 2 = 4 monsters seen on day 2. On day 3 she saw double that amount of monsters, 4 x 2 = 8. On day 4 she saw double that amount of monsters, 8 x 2 = 16. On day 5 she saw double that amount of monsters, 16 x 2 = 32. Altogether Chandra saw 2 + 4 + 8 + 16 + 32 lost monsters = 62 total lost monsters that Chandra needs to lead back to the swamps.
The answer: 62
Reverse engineering the question: Chandra is going on a monster hunt. After a big storm, there have been lost monsters all around the castle grounds for the last 5 days. Chandra wants to rope them all up and return them to the swamps where they will be the most comfortable. On the first day she saw 2 monsters near the castle walls. Every day after that she saw double the amount as the day before. After 5 days how many monsters does she need to lead back to the swamps?


Reasoning and answer: Let x be the number of nickels he is holding. His nickels are worth 5 * x = 5x cents. He has x + 4 dimes. The dimes are worth 10 * (x + 4). The total worth of the nickels and dimes is 5x + 10 * (x + 4) = 70. 5x + 10x + 40 = 70. 15x = 30. x = 2, Steve has 2 nickels in his hand.
The answer: 2
What was the question?
Question: Steve is holding nickels and dimes in his hand. He has 4 more dimes than nickels. He has a total of 70 cents in his hand. How many nickels is he holding?


The second and third tank each have 20 * 2 = 40 fish. So in total there are 20 + 40 * 2 = 100 fish.
The answer: 100
Reverse engineering the question: James has 3 fish tanks. 1 of the tanks has 20 fish in it and the other two have twice as many fish each as the first. How many total fish do they have?


She has 180 minutes to do work because 3 times 60 equals 180. She has already spent 150 minutes on homework because 45 plus 30 plus 50 plus 25 equals 150. She has 30 minutes to finish her project because 180 minus 150 equals 30.
The answer: 30
Reverse engineering the question:
Porche has 3 hours to get all her homework done. Her math homework takes her 45 minutes. Her English homework takes her 30 minutes. Her science homework takes her 50 minutes. Her history homework takes her 25 minutes. She also has a special project due the next day. How much time does she have left to get that project done?