He sells 500 * .8 = 400 newspapers. He sells them for 400 * 2 = $800. He gets a discount of 2 * .75 = $1.5 on the newspapers. So he buys them for 2 - 1.5 = $.5. So he spent 500 * .5 = $250 buying them. That means he made a profit of 800 - 250 = $550.
The answer: 550
Reverse engineering the question: John buys 500 newspapers. Each newspaper sells for $2. He sells 80% of them. He buys them all for 75% less than the price at which he sells them. How much profit does he make?


Reasoning and answer: In one party, the total amount of money collected from the football players is $40 * 60 = $2400. If eight such parties are done in a year, the total amount of money collected from the parties is $2400 * 8 = $19200.
The answer: 19200
What was the question?
Question: To get admission into a school party, each football team member must pay $40. If there are 60 players on the football team and the entire team attends 8 such parties in a year, calculate the total amount of money collected in the 8 parties.


Rudy first runs for 5 * 10 = 50 minutes. Then Rudy runs for 4 * 9.5 = 38 minutes. Rudy runs for a total length of 50 + 38 = 88 minutes.
The answer: 88
Reverse engineering the question: Rudy runs 5 miles at a rate of 10 minutes per mile. Later he runs 4 miles at a rate of 9.5 minutes per mile. What is the total length of time that Rudy runs?


Reasoning and answer: He got 10 / 2 = 5 paid. That means he paid 5 * 3 = $15.
The answer: 15
What was the question?
Question: Bob buys nose spray. He buys 10 of them for a "buy one get one free" promotion. They each cost $3. How much does he pay?


If four pugs can clean their house in 45 minutes, one pug will take 4 * 45 = 180 minutes. Since one pug working alone takes 180 minutes to clean the house, fifteen pugs working together will be able to clean their house in 180 / 15 = 12 minutes.
The answer: 12
Reverse engineering the question: Working together, four pugs can clean their house in 45 minutes. In how many minutes will 15 pugs working together be able to clean their house?


There are 60 minutes in an hour so 1 hour 20 minutes = (60 + 20) minutes = 80 minutes. He will spend a total of 80 + 10 = 90 minutes. 90 minutes is = (60 / 60) hours and 30 minutes = 1 hour 30 minutes = 0130 in 24 - hr time. He has to leave 0130 hours earlier than 0900 i.e. 0900 - 0130 = 0730 hours.
The answer: 730
Reverse engineering the question:
Pete has to take a 10-minute walk down to the train station and then board a 1hr 20-minute train to LA. When should he leave if he cannot get to LA later than 0900 hours? (24-hr time)