Q: John manages to run 15 mph for his whole 5-mile race. The next fastest guy ran the race in 23 minutes. How many minutes did he win the race by?
A: He runs the race in 5 / 15 = 1 / 3 of an hour. So he runs the race in 60 / 3 = 20 minutes. That means he beat the next fastest guy by 23 - 20 = 3 minutes. The answer is 3.
Question: Yuan is 7 years older than his brother David and twice his age. How old is David?
Answer: Let x be David's age. Yuan is seven years older than David, 7 + x = Y years. Yuan is also twice David's age, 2 * x = Y years. Since these two equations equal the same thing, we can write: 7 + x = 2 * x. Subtracting x from both sides we get 7 = x, so David is 7 years old. The answer is 7.
[Question]A man intends to complete a journey of 24 km in 8 hours. If he travels at a speed of 4km/hr for the first four hours, at what speed does he need to travel for the remainder of the journey to be right on time?
[Answer]He covers 4km / hr * 4hrs = 16km in the first 4 hours. He has 24 - 16 = 8km left to cover. He has 8 - 4 = 4 hours to cover the remaining 8km. He has to travel at a speed of 8km / 4hrs = 2km / hr to be right on time. The answer is 2.
Q: In a jar that has 50 ants, the number of ants in the jar doubles each hour. How many ants will be in the jar after 5 hours?
A: After first hour, 50 * 2 = 100 ants. After the second hour, 100 * 2 = 200 ants. After the third hour, 200 * 2 = 400 ants. After the fourth hour, 400 * 2 = 800 ants. After the fifth hour, 800 * 2 = 1600 ants. The answer is 1600.
Question: There were 349 pieces of candy in a bowl. Talitha took 108 pieces and Solomon took 153 pieces. How many pieces of candy remain in the bowl?
Answer: 349 - 108 = 241 and 241 - 153 = 88. There are 88 pieces of candy left in the bowl. The answer is 88.
Q: Jenny had $24 left after spending 3/7 of her money. How much is half of her original amount of money?
A:
Jenny spent 1 - 3 / 7 = 4 / 7 of her money. Since 4 / 7 is equal to $24, then 1 / 7 is equal to $24 / 4 = $6. So, Jenny originally had $6 x 7 = $42. Therefore, half of her original amount of money is $42 / 2 = $21. The answer is 21.