Answer:
Step-by-step explanation:
Let x be the number of buses and y be the number of vans.
We know that there are 5 more buses than vans, therefore, we can set up:

Since a bus transports 55 people and a van transports 12 people, therefore, we can set up:

Now lets solve the above two equations together by substitution

Total number of students and teachers who rode to the zoo in buses
Total number of students and teachers who rode to the zoo in vans