Reasoning and answer: His sister is 10 * 2 = 20 years old. Their age difference is 20 - 10 = 10 years. Therefore when he is 50 she will be 50 + 10 = 60 years old.
The answer: 60
What was the question?
Question: John is 10 years old. His sister is twice his age. When he is 50 years old, how old will his sister be?


Riley has 3 fewer pairs of shoes than Ellie’s 8, so 8 – 3 = 5 pairs of shoes. Together, they have Ellie’s 8 + Riley’s 5 = 13 pairs of shoes.
The answer: 13
Reverse engineering the question: Ellie has 8 pairs of shoes. Riley has 3 fewer. How many pairs of shoes do they have in all?


Reasoning and answer: Trey used 15 sticky strips for 3 / 5 of the remaining decorations after using nails, so he used 15 *  / 3 / 5 = 25 thumbtacks and sticky strips. The 25 decorations were 1 / 3 of the total decorations, so he used 25 / 1 / 3 = 75 total decorations. The nails were 2 / 3 of the decorations, so Trey used 75 decorations * 2 / 3 = 50 nails.
The answer: 50
What was the question?
Question: Trey is hanging wall decorations around his house. He uses a nail for each of two-thirds of them, a thumbtack for each of two-fifths of the rest, and a sticky strip for each of the other decorations. He used 15 sticky strips. How many nails did Trey use?


1 bottle of soap will last for 4 washes and he needs enough bottles for 20 weeks so 20 / 4 = 5 bottles. Each bottle cost $4.00 and he needs 5 bottles so he will spend $4 * 5 = $20.00 on car soap.
The answer: 20
Reverse engineering the question: Jake can wash his car with 1 bottle of car wash soap 4 times. If each bottle costs $4.00, and he washes his car once a week for 20 weeks, how much does he spend on car soap?


Reasoning and answer: Since Dana Point beach has four times the number of sharks in Newport beach, there are 4 * 22 = 88 sharks at Dana Point. In total, the two beaches have 88 + 22 = 110 sharks.
The answer: 110
What was the question?
Question: Dana Point beach has four times the number of sharks as Newport Beach. If Newport Beach has 22 sharks, how many sharks are there in total on the two beaches?


Reasoning and answer: If Keaton climbed his ladder twenty times, he covered a length of 30 * 20 = 600 feet. Reece's ladder, 4 feet shorter than Keaton's ladder, was 30 - 4 = 26 feet long. If Reece climbed the ladder 15 times, he covered a length of 15 * 26 = 390 feet. Keaton and Reece's total length covered while climbing the ladders is 390 + 600 = 990 feet. Since one foot is equal to 12 inches, the total length they climbed the ladders in inches is 12 * 990 = 11880 inches.
The answer: 11880
What was the question?
Question:
Keaton climbed a 30 feet ladder twenty times while working at the construction site. Reece, also working at the same site, climbed a ladder 4 feet shorter than Keaton's ladder 15 times. What's the total length of the ladders that both workers climbed in inches?