Answer this question:There are 15 tables in the school's cafeteria. Each table can seat 10 people. Usually, only 1/10 of the seats are left unseated. How many seats are usually taken?
The cafeteria can seat 15 x 10 = 150 people. Usually, 150 x 1 / 10 = 15 seat are unseated. Thus, 150 - 15 = 135 seats are usually taken.
The answer is 135.

Answer this question:A pipe is clogged so that only 2 ounces of cleaner can run through the pipe per minute. After fifteen minutes, the cleaner has unclogged it enough that 3 ounces can run through per minute. Ten minutes later, the clog is cleared enough for 4 ounces to run through per minute. How many ounces of cleaner were used after 30 minutes?
For 15 minutes at 2 ounces per minute, 2 * 15 = 30 ounces were used. For the next 10 minutes at 3 ounces per minute, 3 * 10 = 30 ounces were used. There are 30 - 15 - 10 = 5 minutes remaining. For the next 5 minutes at 4 ounces per minute, 4 * 5 = 20 ounces were used. After 30 minutes, 30 + 30 + 20 = 80 ounces of cleaner were used.
The answer is 80.

Answer this question:Lucas' father offers to pay him $2 for each window in the house that he cleans. Each floor of Lucas' house has 3 windows; Lucas lives in a 3-story house. To get Lucas to finish the job faster, his father tells him that he will subtract $1 for every 3 days that pass without Lucas finishing the job. In 6 days, Lucas finishes cleaning all the windows in the house. How much will his father pay him, in dollars?
Lucas cleans a total of 3 floors * 3 windows / floor = 9 windows. The windows cleaned earn Lucas 2 dollars each, so Lucas earns 9 windows * $2 / window = $18. For taking 6 days to clean, Lucas' father subtracts 6 days / $3 / day = $2. In total, Lucas' father will pay him $18 - $2 = $16.
The answer is 16.

Answer this question:A class of 12 students was about to share 108 oranges equally among themselves when it was discovered that 36 of the oranges were bad and had to be thrown away. How many oranges less will each student get now than if no orange had to be thrown away?
If the 12 students had shared the 108 oranges, each student would have gotten 108 / 12 = 9 oranges. But 36 were removed so there are 108 - 36 = 72 oranges left. So 12 shared 72 for each to get 72 / 12 = 6 oranges. This is 9 - 6 = 3 less than they would each get if they did not have to throw any orange away.
The answer is 3.