She hand washes them every 4 weeks and there are 52 weeks in a year so she washes them 52 / 4 = 13 times per year. It takes her 30 minutes to hand wash the pillowcases and she does this 13 times per year for a total of 30 * 13 = 390 minutes per year.
The answer: 390
Reverse engineering the question: Every 4 weeks, Helen hand washes her silk pillowcases. It takes 30 minutes to hand wash all of them. In 1 year, how much time does Helen spend hand washing her pillowcases?


Reasoning and answer: Their total age is 15 because 3 x 5 = 15. 15 - X - 2X - (X - 1) is equivalent to 16 = 4X. Maiya is 4 years old because 16 / 4 = 4.
The answer: 4
What was the question?
Question: Maiya has two sisters. The first sister is twice as old as Maiya. The first sister is 1 year younger than Maiya. Their average age is 5. How old is Maiya?


First find the number of substitute teachers left after half quit: 60 teachers / 2 = 30 teachers. Then find how many teachers quit after an hour but before lunch: 30 teachers * 30% = 9 teachers. Then subtract that number from the number of teachers left after one hour to find how many are left after lunch: 30 teachers - 9 teachers = 21 teachers.
The answer: 21
Reverse engineering the question: 50% of substitute teachers walk out after 1 hour of teaching. 30% of the remainder quit before lunch. If 60 substitute teachers show up at 7 AM, how many will be left after lunch?


Reasoning and answer: Mitch needs to keep 500 * 3 = 1500 for docking fees. Thus, he needs to keep 500 + 3 * 500 = $2000 for license, registration, and docking fees. He has 20000 - 2000 = $18000 left to spend on a boat. Therefore, the longest boat he can buy is 18000 / 1500 = 12 feet long.
The answer: 12
What was the question?
Question: Mitch has saved $20000 to finance his boating hobby. A new boat costs $1500 per foot in length. If Mitch needs to keep $500 for a license and registration, and three times that amount for docking fees, how many feet is the longest boat he can buy?


Tina has 5 - 2 = 3 oranges. Tina has 17 - 10 = 7 tangerines. Tina has 7 - 3 = 4 more tangerines than oranges.
The answer: 4
Reverse engineering the question: Tina's bag contains nine apples, 5 oranges, and 17 tangerines. If she took away 2 oranges and 10 tangerines, how many more tangerines than oranges would she have left?


Alex gives his friends a total of 5 friends * 20 meters of silk = 100 meters of silk. This means he has 600 – 100 = 500 meters of silk left in storage. He can therefore make 500 meters of silk / 5 meters of silk per dress = 100 dresses.
The answer: 100
Reverse engineering the question:
Alex makes luxury dresses out of silk. Each dress needs 5 meters of silk and Alex has 600 meters of silk in storage. His friends also want to learn how to make these dresses so Alex gives all 5 of them 20 meters of silk each. He uses the rest to make dresses himself. How many dresses can Alex make?