The cost of the four pizzas is 4 x $10 = $40. The total cost, including the tip, is $40 + $5 = $45. Therefore, Gemma gets a change of $50 - $45 = $5.
The answer: 5
Reverse engineering the question: Gemma ordered four pizzas at $10 each, and she gave a $5 tip to the delivery person. How much change did she get back if she gives one fifty-dollar bill?


Reasoning and answer: At the end of Monday, there are 336 - 124 = 212 books left. At the end of Tuesday, there are 212 + 22 = 234 books.
The answer: 234
What was the question?
Question: There are 336 books in a library. On Monday, 124 books are taken out. On Tuesday, 22 books are brought back. How many books are there now?


We need to add Matt's entire family together so 1 + 2 + 2 + 4 + 2 + 3 = 14. Only 4 people could sleep in the house so 14 - 4 = 10 people would sleep in a tent. Each tent sleeps 2 people and there were 10 people left so 10 / 2 = 5 tents were needed.
The answer: 5
Reverse engineering the question: Matt's entire family was going to spend the week at the lake house for vacation. Matt's family included his mom, dad, his older brother and his wife and their 4 kids. His Uncle Joe and his wife were also coming and would bring their 3 kids. The house only sleeps 4 people. Everyone else would sleep 2 to a tent outside. How many tents would they need?


Reasoning and answer: The bag is now sold for $150 - $135 = $15 less. The discount is 15 / 150 = 1 / 10. Thus, the percent discount is 1 / 10 x 100% = 10%.
The answer: 10
What was the question?
Question: While passing by a store, Miley noticed that a bag that cost $150 last week is now on sale for $135. What percent is the discount?


After giving $5, Lucy has $20 - $5 = $15 left. Since Linda has $15 after receiving $5, then she had $15 - $5 = $10 at the beginning.
The answer: 10
Reverse engineering the question: If Lucy would give Linda $5, Lucy would have the same amount of money as Linda. If Lucy originally had $20, how much money did Linda have at the beginning?


The first five runners took a combined total of 5 * 8 = 40 hours to finish the race. The number of runners who finished the race 2 hours later after the first five is 8 - 5 = 3. The 3 runners who finished the race 2 hours later took a total of 8 + 2 = 10 hours to run the race. Together, the three runners who finished the race in 10 hours took a total of 10 * 3 = 30 hours. All eight runners took 30 + 40 = 70 hours altogether to finish the race.
The answer: 70
Reverse engineering the question:
In a race, there are eight runners. The first five runners finish the race in 8 hours, while the rest of the runners finish the race 2 hours later. Calculate the total time the eight runners took to finish the race.