Q: The sum of Cooper's, Dante's, and Maria's ages is 31. Dante is twice as old as Cooper. Maria is one year older than Dante. How old is Cooper?
A: Let X be the age of Cooper. So Dante is X * 2 years old and Maria is X * 2 + 1 year old. The sum of Cooper's, Dante's, and Maria's ages is X + (X * 2) + (X * 2 + 1) = 31. Combining like terms, we get X * 5 + 1 = 31. Subtracting one from both sides, we get X * 5 = 30. Dividing both sides by 5, we get X = 6 years old. The answer is 6.
Question: The class has to guess how many jellybeans are in a jar the teacher brought in. He lets 4 students make their guesses. The first thinks it contains 100 jellybeans. The second says there are 8 times as many. The third guesses 200 less than the third. The fourth takes the average of the first three guesses, and then adds 25 to it. How many jellybeans did the fourth student guess?
Answer: The second student guessed 800 because 8 x 100 = 800. The third guessed 600 because 800 - 200 = 600. The total guesses of the first three is 1500 because 100 + 800 + 600 = 1500. The average of the first three guesses is 500 because 1500 / 3 = 500. The fourth student guessed 525 because 500 + 25 = 525. The answer is 525.
[Question]At camp Wonka, there are 96 campers. Two-thirds of the campers are boys, and the remaining one-third are girls. 50% of the boys want to toast marshmallows and 75% of the girls want to toast marshmallows. If each camper gets one marshmallow to toast, how many marshmallows do they need?
[Answer]The girls make up one - third of the campers, so there are 96 / 3 = 32 girls. The boys make up two - thirds of the campers, so there are 32 + 32 = 64 boys. There are 32 x 75% = 24 girls who want to toast marshmallows. There are 64 x 50% = 32 boys who want to toast marshmallows. They need 24 + 32 = 56 marshmallows. The answer is 56.
Q: If you double a number and add 5 to the result, then that's 20 more than half of the original number. What's the original number?
A: Let x be the original number. 2 * x + 5 = 20 + x / 2. 2 * x - x / 2 = 15. 4 * x - x = 30. 3 * x = 30. x = 10. The answer is 4.
Question: Kim drives 30 miles to her friend's house. On the way back she has to take a detour that is 20% longer. She spends 30 minutes at her friend's house. She drives at a speed of 44 mph. How long did she spend away from home?
Answer: The trip back was 30 * .2 = 6 miles longer than the trip there. So it was 30 + 6 = 36 miles. So the total drive was 30 + 36 = 66 miles. That means she drove for 66 / 44 = 1.5 hours. She stayed with her friend 30 / 60 = .5 hours. So the total time was 1.5 + .5 = 2 hours. The answer is 2.
Q: Mark plants some strawberries in his backyard. Every month, the number of strawberry plants doubles. After 3 months, Mark digs up 4 strawberry plants and gives them to his friend. If he still has 20 strawberry plants, how many did he initially plant?
A:
First, add the 4 plants Mark gave away to the 20 he has left: 4 + 20 = 24. Then divide this number by 2 to find how many plants Mark had after two months: 24 / 2 = 12. Then divide that number by 2 to find how many plants Mark had after one month: 12 / 2 = 6. Finally, divide that number by 2 to find out how many plants Mark initially planted: 6 / 2 = 3. The answer is 3.