Kelsey turned 25 in 1999 so she was born in 1999 - 25 = 1974. Kelsey's sister is older by 3 years so she was born in 1974 - 3 = 1971. It's currently 2021 and Kelsey's sister was born in 1971 so she is 2021 - 1971 = 50 years old.
The answer: 50
Reverse engineering the question: Kelsey turned 25 in 1999. Her older sister was born 3 years before Kelsey. It's currently 2021. How old is Kelsey's older sister?


Reasoning and answer: Jolyn is 2 + 5 = 7 months older than Aivo. Since Leon is 2 months older than Aivo, then Jolyn is 7 - 2 = 5 months older than Leon.
The answer: 5
What was the question?
Question: Four classmates were comparing their ages based on their birth month. They found out that Jolyn is 2 months older than Therese while Therese is 5 months older than Aivo. Then, Leon is 2 months older than Aivo. How much older in months is Jolyn than Leon?


If Charley bought 30 pencils and lost 6 while moving, she remained with 30 - 6 = 24 pencils. Because she isn't good at keeping track of her pencils, Charley lost 1 / 3 * 24 = 8 more pencils. She currently has 24 - 8 = 16 pencils.
The answer: 16
Reverse engineering the question: Charley bought 30 pencils. She lost 6 pencils while moving to school, and of course, also lost 1/3 of the remaining pencils because she wasn't very good at keeping track of pencils. How many pencils does she currently have?


Reasoning and answer: The weekly salary of Agnes is $15 x 8 = $120. So in a month, Agnes earns $120 x 4 = $480. Therefore, Mila needs to work for $480 / $10 = 48 hours to earn as much as Agnes's monthly earnings.
The answer: 48
What was the question?
Question: There are two babysitters named Mila and Agnes. Mila makes $10 an hour while Agnes makes $15 an hour. Agnes works 8 hours each week. How many hours does Mila need to work to earn as much as Agnes in a month?


Ruel has a total of 4 x 10 = 40 stamps from the four books. He also has 6 x 15 = 90 stamps from the six books. Therefore, he has a total of 40 + 90 = 130 stamps.
The answer: 130
Reverse engineering the question: Ruel has four books of 10 stamps and six books of 15 stamps. How many stamps does Ruel have?


If Lydia has 60 bananas, and Dawn has 40 more, then Dawn has 60 + 40 = 100 bananas. The total number of bananas Dawn and Lydia have is 100 + 60 = 160 bananas. Donna has 200 - 160 = 40 bananas.
The answer: 40
Reverse engineering the question:
Dawn, Lydia, and Donna have a total of 200 bananas. Dawn has 40 more bananas than Lydia. If Lydia has 60 bananas, how many bananas does Donna have?