Of all the scientists taking part in the project, half of them are from Europe, which means 70 * 0.5 = 35 people. The number of researchers from Canada is 70 * 1 / 5 = 14 people. That means there are 70 - 35 - 14 = 21 researchers from the USA.
The answer: 21
Reverse engineering the question: Paul is working at a university. He is part of a big project, which involves 70 scientists in total. Half of them are from Europe and one-fifth are from Canada. The rest are from the USA. How many scientists in this project are from the USA?


Reasoning and answer: The original price of the bag was reduced by $500 x 5 / 100 = $25. So its selling price after a week was $500 - $25 = $475. The price of the bag was again reduced by $475 x 4 / 100 = $19. So, its selling price now is $475 - $19 = $456. Therefore, the total reduction from the selling price is $500 - $456 = $44.
The answer: 44
What was the question?
Question: A bag was originally priced at $500. A week after, the price was reduced by 5%. Since the bag was still not sold, the selling price was reduced by 4% a month after. How much was the total reduction from the original selling price?


Happy has to take 40 / 100 * 15 = 6 more cups of water than she takes currently to reach the recommended water intake levels by her doctor. In total, she is supposed to drink 6 + 15 = 21 cups of water every week.
The answer: 21
Reverse engineering the question: To increase her water intake to the recommended level by her doctor, Happy has to take 40% more cups of water than she takes now. If she is currently drinking 15 cups of water every week, what's the recommended number of cups per week?


Reasoning and answer: First find how many giraffe statues Nancy can make by dividing the total amount of jade by the amount used per giraffe statue: 1920 g / 120 g / giraffe = 16 giraffes. Then multiply that number by the price per giraffe to find how much Nancy earns total from giraffes: 16 giraffes * $150 / giraffe = $2400. Then find how much jade each elephant statue uses by doubling the jade used by the giraffe statues: 120 g / giraffe * 2 = 240 g / elephant. Then find how many elephant statues Nancy can make by dividing the total amount of jade by the amount used per elephant statue: 1920 g / 240 g / elephant = 8 elephant. Multiply that number by the price per elephant to find Nancy's total earnings from elephants: 8 elephants * $350 / elephant = $2800. Finally, subtract Nancy's total earnings from the giraffes from her total earnings from the elephants to find the difference: $2800 - $2400 = $400.
The answer: 400
What was the question?
Question: Nancy carves statues out of jade. A giraffe statue takes 120 grams of jade and sells for $150. An elephant statue takes twice as much jade and sells for $350. If Nancy has 1920 grams of jade, how much more money will she make turning it all into elephants instead of giraffes?


Alex is inviting 84 * 2 / 3 = 56 guests. Bridgette and Alex’s guests will need 84 + 56 = 140 plates. The caterer makes 10 extra plates, so they will need 140 + 10 = 150 plates. To put 8 asparagus spears on each plate, the caterer will need 150 * 8 = 1200 asparagus spears.
The answer: 1200
Reverse engineering the question: Bridgette and Alex are getting married. Bridgette is inviting 84 guests, and Alex is inviting two thirds of that number of guests. They hired a caterer to make a plated meal for each guest at the wedding reception. The caterer always makes ten extra plates just in case something goes wrong. Each plate of steak and asparagus in garlic butter will have 8 asparagus spears on it. How many asparagus spears will the caterer need in all?


40 / 4 = 10 kids went tubing. 10 / 2 = 5 kids went rafting and tubing.
The answer: 5
Reverse engineering the question:
There were 40 kids on Lake Pleasant. A fourth of the kids went tubing, but only half of the tubers went rafting. How many of the kids who joined the rafting excursion were also on the tubing excursion?