Answer:
There would be 36 adults on the field trip.
Explanation:
Given,
There are 4 chaperone for every 15 students who attend a school field trip,
So, the ratio of the chaperone and students =

Let there are x chaperone for 135 students,
So, the ratio of the chaperone and students =




Hence, there would be 36 adults on the field trip.