Question: 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?
Answer: 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: Since Jason started investing, he has earned the same amount he invested twice over in 5 months. If Jason's investment currently is worth $90, how much has he been earning per month from his investment assuming he has been earning an equal amount of returns each month?
Answer: Let's say Jason invested x amount of money. Since Jason started investing, he has earned the same amount he invested twice over in 5 months, meaning he has earned x + 2 * x = $90. This evaluates to 3x = $90. The total amount of money that Jason invested is x = $90 / 3. Jason invested x = $30. The total amount of money that Jason has earned from his investments is $90 - $30 = $60. If he earned an equal amount of money from the investment in five months, his monthly returns is 60 / 5 = $12. The answer is 12.

Question: The number of math problems that Marvin practiced today is three times as many as the number of problems he solved yesterday. His friend, Arvin, has practiced twice as many math problems on each day. How many math problems have they practiced altogether if Marvin solved 40 math problems yesterday?
Answer: If Marvin solved 40 math problems yesterday, he has solved 40 * 3 = 120 math problems today. The total number of math problems that Marvin has practiced is 120 + 40 = 160. Arvin has practiced twice as many as Marvin, so has practiced 160 * 2 = 320 problems. Together, Marvin and Arvin have solved 320 + 160 = 480 math problems. The answer is 480.

Question: The total age of the people in Kaydence's family is 200. If Kaydence's father is 60 years old, Kaydence's mother 2 years younger than Kaydence's father, Kaydence's brother 1/2 the age of Kaydence's father, and Kaydence's sister 40 years old, how old is Kaydence?
Answer:
If Kaydence's father is 60 years old, her mother is 60 - 2 = 58 years old. The total age of the mother and father is 60 + 58 = 118 years. Kaydence's brother is half the father's age, which is 1 / 2 * 60 = 30 years. The total age of Kaydence's father, mother, and brother is 30 + 118 = 148 years. If you add Kaydence's sister's age to the total age of the father, mother, and brother, you get 148 + 40 = 188 years. If everyone's age in the family is 200, then Kaydence's age is 200 - 188 = 12 years old. The answer is 12.