Q: John visits three different countries. He stays in the first country for 2 weeks and he spends twice as long in each of the other two countries. How much time does he spend on the trip?
A: He spends 2 * 2 = 4 weeks in the other two countries. So he spends 2 * 4 = 8 weeks in those countries combined. That means he is gone for 2 + 8 = 10 weeks. The answer is 10.
Question: Lizzy's school choir has a mixture of 80 blonde and black-haired girls. Their teacher decides to add 10 more girls to the choir, who turns out to be blonde. If there were 30 blonde-haired girls in the choir initially, how many black-haired girls are present?
Answer: The total number of girls in the choir is 80 + 10 = 90 girls. The total number of blondes in the choir after 10 more are added is 30 + 10 = 40 blonde - haired girls. From the total number, the number of black - haired girls is 90 - 40 = 50 black - haired - girls. The answer is 50.
[Question]There are 35 books on the cart. There are five fiction books, 4 more non-fiction books than fiction books, 2 times as many autobiographies as fiction books, and the rest picture books. How many books were picture books?
[Answer]There are 5 + 4 = 9 non - fiction books on the cart. There are 2 * 5 = 10 autobiographies on the cart. There are 5 + 9 + 10 = 24 fiction, non - fiction, and autobiography books on the cart. There are 35 - 24 = 11 picture books on the cart. The answer is 11.
Q: Francine wants to know if a local chemical plant is releasing toxic waste that makes the frogs mutate. In one local pond, she catches 5 frogs with extra legs, 2 frogs with 2 heads, two frogs that are bright red, and 18 normal frogs. What percentage of the frogs have mutated, rounded to the nearest integer?
A: First add up the numbers of the three kinds of mutant frog: 5 frogs + 2 frogs + 2 frogs = 9 frogs. Then add that number to the number of normal frogs to find the total number of frogs: 9 frogs + 18 frogs = 27 frogs. Finally, divide the number of mutant frogs by the total number of frogs and multiply by 100% to find the percentage of frogs that are mutants: 9 frogs / 27 frogs * 100% = 33.333...%, which rounds to 33%. The answer is 33.
Question: Stephen rides his bicycle to church. During the first third of his trip, he travels at a speed of 16 miles per hour. During the second third of his trip, riding uphill, he travels a speed of 12 miles per hour. During the last third of his trip, he rides downhill at a speed of 20 miles per hour. If each third of his trip takes 15 minutes, what is the distance Stephen rides his bicycle to church, in miles?
Answer: 15 minutes is 15 / 60 = 0.25 hours. Traveling 15 minutes at 16 miles per hour, Stephen travels 16 * 0.25 = 4 miles. Traveling 15 minutes at 12 miles per hour, Stephen travels 12 * 0.25 = 3 miles. Traveling 15 minutes at 20 miles per hour, Stephen travels 20 * 0.25 = 5 miles. All together, Stephen travels 4 + 3 + 5 = 12 miles. The answer is 12.
Q: There are 30 students in Ms. Leech's class. Twice as many girls as boys are in the class. There are 10 boys in the class and each boy today brought 5 cups for science activity class as Ms. Leech had instructed. If the total number of cups brought by the students in the class is 90, how many cups did each girl bring?
A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
If there are 30 students in Ms. Leech's class, and the number of boys is 10, the number of girls in Ms. Leech class is 30 - 10 = 20. If each boy brought 5 cups for the science activity, the total number of cups brought by the boys is 5 * 10 = 50 cups. The number of cups that the girls brought is 90 - 50 = 40 of the total number. Since the number of girls in the class is 20, each girl brought 40 / 20 = 2 cups each. The answer is 2.