[Question]Randy just turned 12 and started playing the piano. His friend Sheila told him about the 10,000-hour rule which says, after 10,000 hours of practice, you become an expert or master in your field. If Randy wants to become a piano expert before he is 20, how many hours a day will he need to practice if he practices every day, Monday – Friday, and takes two weeks off for vacation each year?
[Answer]Randy has 20 – 12 = 8 years until he is 20. He must practice 10,000 hours / 8 years = 1,250 hours a year to become an expert. There are 52 weeks in a year – 2 weeks of vacation Randy plans to take = 50 weeks of practice for Randy. Randy will practice Monday – Friday, which is 5 days a week, so 50 weeks x 5 days = 250 days of practice each year. Randy will need to practice 1250 hours / 250 days = 5 hours each day. The answer is 5.
Q: It takes Derek 9 minutes to walk a mile if he doesn't have to walk with his brother. If he has to take his brother it takes 12 minutes to walk a mile. How many minutes longer would it take him to walk 20 miles if he had to take his brother?
A: Alone it would take him 9 * 20 = 180 minutes. With his brother, it would take him 12 * 20 = 240 minutes. 240 - 180 = 60 more minutes. The answer is 60.
Question: On Thursday the Meat Market sold 210kg of ground beef. On Friday they sold twice that amount. On Saturday they only sold 130kg. On Sunday they sold half of what they sold Saturday. If they originally planned to sell only 500kg, how much meat did they sell beyond their original plans?
Answer: On Friday they sold 210 × 2 = 420kg. On Sunday they sold 130 ÷ 2 = 65kg. They sold a total of 210 + 420 + 130 + 65 = 825kg of meat. Meat Market sold an extra 825 - 500 = 325kg of meat beyond their original 500kg plans. The answer is 325.
[Question]Blinky wants to make a three-layer birthday cake for her mom. The recipe for the smallest layer of the cake requires 2 cups of sugar. If the second layer is twice as big as the first and the third layer is three times larger than the second, how many total cups of sugar will she need for the third layer?
[Answer]Since the second layer is twice as big as the first, then it requires 2 * 2 = 4 cups of sugar. Since the third layer is three times bigger than the second, then it requires 4 * 3 = 12 cups of sugar. The answer is 12.
Q: Jane is trying to decide whether to buy a house or a trailer. A house costs $480,000 and a trailer costs $120,000. Each loan will be paid in monthly installments over 20 years. How much more is the monthly payment on the house compared to the trailer?
A: First find how many months the loans last: 20 years * 12 months / year = 240 months. Then divide the cost of the house by the number of payments to find the monthly payment before interest: $480,000 / 240 months = $2000 / month. Then do the same thing to find the monthly payment before interest on the trailer: $120,000 / 240 months = $500 / month. Then subtract the cost of the trailer payment from the cost of the house payment to find the difference: $2000 / month - $500 / month = $1500 / month. The answer is 1500.
Question: Viviana has five more chocolate chips than Susana, while Susana has 3/4 as many vanilla chips as Viviana. If Viviana has 20 Vanilla chips and Susana 25 chocolate chips, calculate the total number of chips they have together.
Answer:
Viviana has 20 Vanilla chips. Susana has 25 chocolate chips. Viviana has 25 + 5 = 30 chocolate chips. Susana has 3 / 4 * 20 = 15 Vanilla chips. They have 30 + 25 = 55 chocolate chips together. Together they have 20 + 15 = 35 vanilla chips. Together they have 35 + 55 = 90 chips. The answer is 90.