Xiao Ming asked the teacher how old he was this year. The teacher said, "When I was your age, you were only 3 years old; When you reach my age, I will be 33 years old. "

Solution: Suppose the teacher is X years older than Xiaoming.

3+X is Xiao Ming's age, and 33-X is the teacher's age.

Get 3+x+x = 33-x.

The solution is X= 10.

Xiaoming is 3+X= 10+3= 13 years old this year.

Teacher 13+ 10=23 years old.