He had 80 - 20 = 60 after the donation. He kept 60 / 2 = 30 after giving half to his brother. So he has 30 * 3 = 90 coins. He then does 1 more donation and has 90 - 10 = 80 coins left.
The answer: 80
Reverse engineering the question: Jake amasses a fortune of 80 bitcoin. He donates 20 bitcoins to charity. He then gives half of all the bitcoins to his brother. After that, he triples the number of bitcoins he has. Then he donates another 10 coins. How many coins does he have?


Reasoning and answer: It's a 100 - foot fence, and Ben whitewashed 10 feet, so there are 100 - 10 = 90 feet left after Ben is done. Billy whitewashed a fifth of that, or 90 / 5 = 18 feet. There is now 90 - 18 = 72 feet of fence left. Johnny whitewashes a third of that, or 72 / 3 = 24 feet. That leaves 72 - 24 = 48 feet of fence left to be whitewashed.
The answer: 48
What was the question?
Question: Tom Sawyer has tricked his friends into whitewashing Aunt Polly's 100-foot fence. His first friend, Ben, whitewashed 10 feet. His second friend Billy whitewashed a fifth of the remaining fence. A third friend, Johnny, whitewashed a third of the fence that was left after that. How much of the fence still needs to be whitewashed?


If the two men each bought 30 apples, together they bought 2 * 30 = 60 apples. Since the two men each bought 30 apples, 20 less than the total number of apples bought by each woman, each woman bought 20 + 30 = 50 apples. The total number of apples bought by the women is 3 * 50 = 150. Altogether, the two men and three women bought 60 + 150 = 210 apples.
The answer: 210
Reverse engineering the question: How many apples did two men and three women buy at a certain store if the two men each bought 30 apples, 20 less than the number of apples bought by each woman?


Reasoning and answer: The bed cost 75 * 10 = $750. So everything cost 750 + 75 = $825. He gets 825 * .2 = $165 off. So that means he pays 825 - 165 = $660.
The answer: 660
What was the question?
Question: James decides to buy a new bed and bed frame. The bed frame is $75 and the bed is 10 times that price. He gets a deal for 20% off. How much does he pay for everything?


100 - 40 = 60 percent of students are remaining. 60 / 2 = 30 percent are present in school.
The answer: 30
Reverse engineering the question: Forty percent of the students have elected to learn from home during the pandemic. The remaining students are divided into two equal groups, only one of which is physically in school on any day. What percent of students are present in school?


Hillary sells 3 crafts for 12 dollars each, for a total of 3 crafts * $12 / craft = $36. She receives an extra 7 dollars from a customer, increasing the total to $36 + $7 = $43. She then deposits 18 dollars in the bank, leaving her with $43 - $18 = $25.
The answer: 25
Reverse engineering the question:
At a flea market, Hillary sells handmade crafts for 12 dollars per craft. Today, Hillary sells 3 crafts and is given an extra 7 dollars from an appreciative customer. Later on, Hillary deposits 18 dollars from today's profits into her bank account. How many dollars is Hillary left with after making the deposit?