1. In a math exam, the teacher gave 33 questions, which stipulated that 8 points would be deducted if one answer was correct, and 3 points would be deducted if one answer was wrong. Xiao Ming answered all the questions, but got 0. How many questions did Xiaoming answer correctly?

Solution: Set X correctly.

8x-(33-x)*3=0

x=9

2. A person takes a train from A City Road to B City, and falls asleep after walking 50% of the way. When he woke up, he found that the remaining distance was 50% of the distance he had walked before going to bed. What percentage is left in the whole journey?

1-50%-50%*50%=25%

3★. A car goes from A to B. If the speed is increased by 20%, it can arrive 1 hour earlier than the original time; If you drive at the original speed of 120km and then speed up by 25%, you can arrive 40 minutes earlier. How many kilometers is it between A and B?

1/( 1+20%)=5/6

1/( 1+25%)=4/5

6*( 1-4/5)= 1.2 (hours) =72 (minutes)

120/(72-40)*72=270 (km)

A: The distance between A and B is 270 kilometers.