How many boxes does she need over all

Hey there.

Devon has 80 books in total to pack. She packs 20 books in each box; therefore, we need to divide our total, 80, by 20 to solve for how many boxes she has. Let's set up an equation for this.

We know that there is 20 books per whole box, so we should set our variable expression as '20n'. "n" symbolizes how many boxes is required. We also know that 80 is our total books. This is all we need in order to set up an equation and solve.

We have the following expression:
20n = 80; our goal is to solve for n. To do this, we must divide both sides of the equation by 20. This will isolate and solve for our variable.

20x = 80
20n / 20 = n
80 / 20 = 4

n = 4 is your answer.

This means that Devon will need a total of 4 boxes to pack with 80 books.

I hope this helps!