Answer:

Step-by-step explanation:
The algebraic expression states that
"The class we divided into four equal groups."
We have our expression right at the word of "divided", therefore the answer would be a division problem.
w over 4 fits this because it fits the expression, w - class and 4 - amount of groups.
4 + w - Would be the class added four groups
4w - The class multiplies four more groups
4 - w - Four groups was taken from the class
12 students would create 4 groups, if they get 8 cubic meters per hour and they have 5 hours, the equasion would look like: (8*5)*4)=160. They would clear 160 cubic meters in 5 hours.