Question: Yella's computer usage last week was 91 hours. If she plans to use the computer 8 hours a day for this week, how much less ​is her computer usage for this week?
Answer: Yella can use the computer 8 x 7 = 56 hours for this week. Therefore, Yella's computer usage for this week is 91 - 56 = 35 hours lesser than her computer usage last week. The answer is 35.

Question: It takes 10 minutes to wash a car, 15 minutes to change oil, and 30 minutes to change a set of tires. If mike washes 9 cars, changes the oil on 6 cars, and changes two sets of tires how many hours did he work?
Answer: He spent 10 minutes * 9 cars = 90 minutes washing cars. He spent another 15 minutes * 6 cars = 90 minutes changing oil. He spent 2 cars * 30 minutes = 60 minutes changing tires. He spent 90 minutes + 90 minutes + 60 minutes = 240 minutes working. He spent 240 minutes / 60 minutes = 4 hours working. The answer is 4.

Question: During a commercial break in the Super Bowl, there were three 5-minute commercials and eleven 2-minute commercials. How many minutes was the commercial break?
Answer: The 5 - minute commercials were 3 * 5 = 15 minutes in total. The 2 - minute commercials were 2 * 11 - 22 minutes in total. The commercial break was 15 + 22 = 37 minutes long. The answer is 37.

Question: A package of candy has 3 servings with 120 calories each. John eats half the package. How many calories did he eat?
Answer:
There were 3 * 120 = 360 calories in the package. So he ate 360 / 2 = 180 calories. The answer is 180.