Four 4th grade classes are going on a field trip to the aquarium. three classes have 18 students and one class has 10. parents will be driving the students in their own vechicle and each vechicle can hold 5 students.

They will need 13 buses

If you have 18 in three of the classes you will need three buses per class

Each van holds 5 kids divide 18 by 5 you get 3 (plus a remainder we will get back to that later)

and 2 vans for the class of 10

So far we are at 11 buses

But there is that remainder you will need 2 more for them

So that puts us at 13 buses

Hope this helps

each side has a different length.  

step-by-step explanation: