Sam and Drew have a combined age of 54. Sam is half of Drew's age. How old is Sam?
Let's think: Let x be Drew's age. Sam is (1 / 2)x. x + (1 / 2)x = 54. (3 / 2)x = 54. 3x = 108. x = 36. Sam is 36 / 2 = 18 years old.. The answer is: 18.

In the fall, 20,000 high school students apply to Harvard University for college. In the spring, 5% of those 20,000 students are accepted to the university. Of the students who are accepted, 90% choose to attend the university, and the other 10% choose to go to other schools. How many students choose to attend Harvard University?
Let's think: The number of students accepted to the university is 20,000 * 0.05 = 1,000 students. The number of students who choose to attend the university is 1,000 * 0.9 = 900 students.. The answer is: 900.

Amaya is watching a movie that she finds kind of boring, so she keeps tuning out and having to rewind it to catch what she missed. She watches 35 minutes before she realizes she needs to rewind the movie to catch something she missed, a process that adds 5 minutes to her total viewing time. She watches the movie for another 45 minutes but has to rewind it again, adding 15 minutes to her total time. Finally, she watches the last 20 minutes uninterrupted. If she added up the duration of the film plus all the times she had to rewind and re-watch parts, how many minutes did it take her to watch the movie?
Let's think: Amaya watches the movie without rewinding for 20 minutes + 15 minutes + 45 minutes + 20 minutes = 100 minutes duration of the movie. However, Amaya also spent extra time re - watching parts she rewound, for 5 minutes + 15 minutes = 20 minutes. In all, Amaya spent 100 minutes + 20 minutes = 120 minutes watching the movie.. The answer is: 120.

Cindy can jump rope for 12 minutes before tripping up on the ropes. Betsy can jump rope half as long as Cindy before tripping up, while Tina can jump three times as long as Betsy. How many more minutes can Tina jump rope than Cindy?
Let's think:
Betsy jumps half as long as Cindy, who jumps for 12 minutes so Betsy jumps 12 / 2 = 6 minutes. Tina jumps three times as long as Betsy, who jumps for 6 minutes so Tina jumps 3 * 6 = 18 minutes. Tina can jump for 18 minutes and Cindy and jump for 12 minutes so Tina can jump 18 - 12 = 6 minutes longer.. The answer is: 6.