In the sixth grade of primary school, a famous math teacher tutored students. Page 56, question 3
Solution: Each bus carries X people, and the bus carries (X+20 people).
10X+5(X+20)=550
10X+5X+ 100=550
15x+ 100=550
15X=450
X=30
X+20=50
A: Each bus carries 30 passengers and each bus carries 50 passengers.