Ten students raised a total of $20 x 10 = $200. There are 30 - 10 = 20 students who raised $30 each. Twenty students raised a total of $30 x 20 = $600. Therefore, the students raised a total of $200 + $600 = $800.
The answer: 800
Reverse engineering the question: Thirty students run in a charity race to raise money for the hurricane victims. Ten of the students raised $20 each. The rest of the students raised $30 each. How much did the students raise in all?
Reasoning and answer: There are 52 weeks in a year. For the first year, Thomas received 52 x 50 = $2600. In the second year, Thomas earned 9 x 30 = $270 a week. In a year, Thomas earned 52 x 270 = $14,040. The total for the two years is 14040 + 2600 = 16640. In 2 years, Thomas' weekly expenses amounted to $35 x (52 x 2) = $35 x 104 = $3640. By the end of 2 years, Thomas would have saved $16640 - $3640 = 13000. Thomas still needs $15,000 - 13000 = $2000.
The answer: 2000
What was the question?
Question: Thomas started saving for a car almost 2 years ago. For the first year, his weekly allowance was $50. In the second year, he got a job that pays $9 an hour at a coffee shop and worked 30 hours a week, so his parents discontinued his allowance. If the car he wants to buy is $15,000 and he spends $35 a week on himself, how much more money does Thomas need to buy the car by the end of the 2 years?
Sylvia got 50 / 5 = 10 incorrect answers. This means she got 50 - 10 = 40 correct answers. Sergio got 50 - 4 = 46 correct answers. So, Sergio got 46 - 40 = 6 more correct answers than Sylvia.
The answer: 6
Reverse engineering the question: Sylvia had one-fifth of incorrect answers in the exam, while Sergio got 4 mistakes. If there were 50 questions, how many more correct answers does Sergio have than Sylvia?
Reasoning and answer: The second guinea pig eats 2 x 2 = 4 cups of food. The third guinea pig eats 4 + 3 = 7 cups of food. Therefore, Rollo needs a total of 2 + 4 + 7 = 13 cups of food for the guinea pig.
The answer: 13
What was the question?
Question: Rollo has 3 guinea pigs, the first guinea pig eats 2 cups of food, the second guinea pig eats twice as much as the first one, and the third guinea pig eats 3 cups more than the second one. How many cups of food does Rollo need to feed all his Guinea pigs?
The distance between Arizona and New York is 2,000 miles by plane. The distance between Arizona and New York is 40% greater by car, which is 40% * 2,000 = 800 miles. This results in a total of 2,000 + 800 = 2,800 miles between Arizona and New York by car. If Missouri is in the middle of the way between Arizona and New York, someone would drive half of the distance to go from Missouri to New York, which is 2,800 / 2 = 1,400.
The answer: 1400
Reverse engineering the question: The distance between Arizona and New York is around 2,000 miles by plane. The distance between the 2 different US states increases by 40% if someone decides to drive instead of flying. Missouri is midway between Arizona and New York. How far away is Missouri from New York if someone decides to go by car?
Accommodation is 15% * $1000 = $150. Food is 30% * $1000 = $300. Entertainment is 25% * $1000 = $250. Coursework materials are thus $1000 - ($150 + $300 + $250) = $300.
The answer: 300
Reverse engineering the question:
James is a first-year student at a University in Chicago. He has a budget of $1000 per semester. He spends 30% of his money on food, 15% on accommodation, 25% on entertainment, and the rest on coursework materials. How much money does he spend on coursework materials?