Let J represent John's age. We have J + 9 = 3(j 11). So, J + 9 = 3J 33. So, 9 = 2J 33. So, 42 = 2J. Which means that John's age is J = 42 / 2 = 21.
The answer: 21
Reverse engineering the question: 9 years from now, John will be 3 times as old as he was 11 years ago. How old is he now?
Reasoning and answer: The first game was 100 * .8 = 80 hours of grinding. So it was 100 - 80 = 20 hours of good gameplay. The expansion brought the time of good gameplay to 20 + 30 = 50 hours.
The answer: 50
What was the question?
Question: James gets bored with his game so decides to play a different one. That game promises 100 hours of gameplay but 80% of that is boring grinding. However, the expansion does add another 30 hours of enjoyable gameplay. How much enjoyable gameplay does James get?
If for every 10 days worked Andrew earns 1 day of vacation, then over 300 days worked he would have earned 300 / 10 = 30 days of vacation. We know he took 5 days off in March and that in September twice as much. That means in September he took 5 * 2 = 10 days off. In total, Andrew has used 5 vacation days in March and another 10 in September. Therefore, he has used 5 + 10 = 15 vacation days. If Andrew earned 30 days of vacation but has only used 15, then he can still take another 30 - 15 = 15 days off.
The answer: 15
Reverse engineering the question: Andrew works in a company that provides a generous vacation allotment: for every 10 days worked, you get 1 vacation day. If last year Andrew worked 300 days and took 5 days off in March and twice as many in September, how many more vacation days can Andrew still take?
Reasoning and answer: After baking cookies, Lucy had 500 240 = 260g of flour left. She accidentally spilled half of this, which means she had 260 * 0.5 = 130g of flour left. She therefore needs 500 130 = 370g of flour.
The answer: 370
What was the question?
Question: Lucy has been trying new recipes and wants to make sure she keeps the cupboard stocked with ingredients. She had a 500g bag of flour in the cupboard at the start of the week. She used 240g when she baked cookies on Tuesday, and accidentally spilled half of what was left when she was putting the flour away. If Lucy wants a full bag of flour in the cupboard, how much flour does she need to buy, in grams?
Philip has 50 / 100 * 20 = 10 more ducks than cows. Which means he has 20 + 10 = 30 ducks. So Philip's cows and ducks sum up to 20 + 30 = 50 animals. If there are 50 cows and ducks, that means Philip has 1 / 5 * 50 = 10 pigs. In total Philip has 50 + 10 = 60 animals on his farm.
The answer: 60
Reverse engineering the question: Philip has a farm with animals. He has 20 cows, 50% more ducks. Philip also has as many pigs as one-fifth of ducks and cows in total. How many animals does Philip have on his farm?
Her goal is 1 hour a day for 5 days so on a weekly basis, she exercises 1 * 5 = 5 hours. If she works 5 hours a week for 8 weeks then she exercises 5 * 8 = 40 hours in 8 weeks.
The answer: 40
Reverse engineering the question:
Jane's goal is to exercise 1 hour a day, 5 days a week. If she hits her goal weekly for 8 weeks, how many hours has Jane exercised?