Question: Bill is trying to control the pests in his garden. Each spider he introduces eats 7 bugs, and each time he sprays the garden he reduces the total bug population to 80% of what it was previously. If the garden has 400 bugs to start, and Bill sprays once and introduces 12 spiders, how many bugs are left?
Answer: First find the total bug population after spraying: 80% * 400 bugs = 320 bugs. Then find the total number of bugs each spider eats: 12 spiders * 7 bugs / spider = 84 bugs. Then subtract that number from the number of bugs left after spraying to find final number of bugs: 320 bugs - 84 bugs = 236 bugs. The answer is 236.
[Question]Sabrina went to the library and found a historical series novel called The Rangers Apprentice. There are 14 books in the series, and each book has 200 pages. She read four books in a month and half the number of books remaining in the second month. What's the total number of pages Sabrina has to read to finish the whole series?
[Answer]The total number of pages in the series is 14 books * 200 pages / book = 2800 pages. Sabrina read 4 books * 200 pages / book = 800 pages in the first month. She still has 14 books - 4 books = 10 books after reading four books. In the second month, she read 1 / 2 * 10 books = 5 books. The total number of pages she read is 5 books * 200 pages / book = 1000 in the second month. In total, Sabrina 1000 pages + 800 pages = 1800 pages in two months. Sabrina has to read 2800 pages - 1800 pages = 1000 more pages to complete the total series. The answer is 1000.
Q: Dennis collected 10 rocks. He put all of them in his aquarium but his fish ate half of them. He was able to make the fish spit two out. How many of Dennis's rocks are left?
A: Dennis had 10 / 2 = 5 rocks left after the fish ate them. He made the fish spit two out, which left Dennis with 5 + 2 = 7 rocks. The answer is 7.
Question: The green piece of yarn is 156 cm long. The red yarn is 8 cm more than three times the length of the green yarn. What is the number of centimeters in the total length for the 2 pieces of yarn?
Answer: Green = 156 cm. Red = 3 * 156 + 8 = 476 cm. 156 + 476 = 632 cm of yarn. The two pieces of yarn have a length of 632 centimeters. The answer is 632.
[Question]Mary has 5 green crayons and 8 blue crayons of different shades. If she gives out 3 green crayons and 1 blue crayon to Becky, how many crayons does she have left?
[Answer]She had 5 + 8 = 13 crayons to start with. She gave out 3 + 1 = 4 crayons to Becky. She will have 13 - 4 = 9 crayons left. The answer is 9.
[Question]Mr. Grey is purchasing gifts for his family. So far he has purchased 3 polo shirts for $26 each; 2 necklaces for $83 each; and 1 computer game for $90. Since Mr. Grey purchased all those using his credit card, he received a $12 rebate. What is the total cost of the gifts after the rebate?
[Answer]
Mr. Grey paid $26 / shirt x 3 shirts = $78 on polo shirts. He paid $83 / necklace x 2 necklaces = $166 on necklaces. So, he paid $78 + $166 + $90 = $334 for the gifts. After the rebate, the total cost of the gifts is now $334 - $12 = $322. The answer is 322.