Answer: They will need 3 total buses to fit all of the teachers and students.
Step-by-step explanation: If there are 14 students and 2 teachers with each class, that is a total of 16 people. Multiply 16 by 3 and you get 48 total people going on the field trip. Divide 48 by 20 and you get 2.4, which means two buses will be filled up to the max and they will need an extra bus to fit the rest. Hence, your answer: 3 total buses.