Candace decides to enter a race. The race is run in 4 segments, with racers eliminated at the end of each segment. 10 racers are eliminated after the first segment. A third of the remaining racers are eliminated after the next section. Half of the remaining racers are eliminated before the last leg of the race. If 100 racers started the race, how many will run in the final section of the race? Give the rationale and then the answer.
Let's think step by step. After the first segment, there are 100 10 = 90 racers left in the race. After the second segment, 90 / 3 = 30 racers are eliminated. This leaves 90 30 = 60 racers to compete in the third segment. After the third segment, 60 / 2 = 30 more racers are eliminated. This leaves 60 30 = 30 racers to run in the final section of the race.. The answer is: 30.

An elevator is on the 9th floor. It goes down 7 floors, then up 3 floors, then up 8 floors. If the elevator is on the top floor, how many floors are there in the building? Give the rationale and then the answer.
Let's think step by step. From the 9th floor, the elevator went down to the 9 - 7 = 2nd floor. Then went up to the 2 + 3 = 5th floor. Then, went up to the 5 + 8 = 13th floor; hence there are 13 floors in the building.. The answer is: 13.

Emma buys 2 containers of milk every school day for lunch. She does not go to school on the weekends. How many containers of milk does she buy in 3 weeks? Give the rationale and then the answer.
Let's think step by step. There are 5 school days in a week: 5 days / week x 2 containers of milk / day = 10 containers of milk every week. Finally the number of container for 3 weeks is 3 weeks x 10 containers / week = 30 containers.. The answer is: 30.