Answer:
7 fossils
Explanation:
Find the cost for transportation by multiplying 20 by 5, since it is $5 per student and there are 20 students
20(5)
= 100
Subtract this from 128, since they raised $128
128 - 100
= 28
This means they have $28 to spend on fossils.
To find how many they can buy, divide 28 by 4, since they are $4 each
28/4
= 7
So, they can buy 7 fossils with the money they have left