[Question]In ten years, I'll be twice my brother's age. The sum of our ages will then be 45 years old. How old am I now?
[Answer]Let X be my age now. In ten years, I'll be X + 10 years old. In ten years, my brother will be (X + 10) * 1 / 2 years old. In ten years, (X + 10) + (X + 10) * 1 / 2 = 45. So (X + 10) * 3 / 2 = 45. X + 10 = 45 * 2 / 3 = 30. X = 30 - 10 = 20 years old. The answer is 20.
Q: There are 4 more Muscovy ducks than Cayugas, and 3 more than twice as many Cayugas as Khaki Campbells. If there are 90 ducks total, how many Muscovies are there?
A: Let x represent the number of Khaki Campbell ducks. Cayugas:3 + 2x. Muscovies:4 + (3 + 2x) = 7 + 2x. Total: x + 3 + 2x + 7 + 2x = 90. 5x + 10 = 90. 5x = 80. x = 16. Muscovy: 7 + 2(16) = 39. The answer is 39.
Question: Michelle is bringing sandwiches to work to give to her co-workers. She gives 4 sandwiches to one of her co-workers and keeps twice this amount for herself. If she had originally made 20 sandwiches, how many sandwiches does she have left to give to her other co-workers?
Answer: Michelle kept 4 sandwiches * 2 = 8 sandwiches for herself. This leaves 20 total sandwiches – 4 sandwiches for a coworker – 8 sandwiches for herself = 8 sandwiches for her other co - workers. The answer is 8.
[Question]Tracy has a charity book collection store from which she receives book donations from members of her town. Any person who wants to borrow a book is free to do so as long as they return the book after they've finished reading. She has already received 300 book donations. If ten people come and donate five books each in a week, and a total of 140 books are borrowed by other people to read, calculate the total number of books she has remaining in the store?
[Answer]The ten people donated 10 * 5 = 50 books. The total number of books in her store after the new donations is 300 + 50 = 350 books. When some of the books are borrowed, her total collection becomes 350 - 140 = 210 books. The answer is 210.
Q: There are 350 trees in the park, 70% of which are pine trees. How many are not pine trees?
A: There are 350 x 70 / 100 = 245 pine trees. Therefore, 350 - 245 = 105 trees are not pine trees. The answer is 105.
Question: Aaron and his brother Carson each saved up $40 to go to dinner. The bill is 3/4 of their total money. After, they go out for ice cream. Each scoop costs $1.5 and they get the same amount as each other. If they leave with $1 in change each, how many scoops did they each buy?
Answer:
They had $80 saved up because 2 x 40 = 80. They spent $60 because 80 x (3 / 4) = 60. They had $20 left for ice cream because 80 - 60 = 20. They had $2 left after leaving the ice cream shop because 2 x 1 = 2. They spent $18 on ice cream because 20 - 2 = 18. The bought 12 scoops of ice cream because 18 / 1.5 = 12. The each bought 6 scoops because 12 / 2 = 6. The answer is 6.