A delivery truck is transporting boxes of two sizes: large and small.

Question

A delivery truck is transporting boxes of two sizes: large and small. The large boxes weigh
45

pounds each, and the small boxes weigh
15

pounds each. There are
120

boxes in all. If the truck is carrying a total of
3450

pounds in boxes, how many of each type of box is it carrying?

Answer 1

Hi Elijah;

 

First choose variables to represent the unknowns:

Let L = # large boxes

Let s = # small boxes

 

Now make equations from the information given:

L + s = 120

45L + 15s = 3450

 

Let's use substitution to solve:  From 1st equation solve for s

s = 120 - L

 

Substitute that into 2nd equation to solve for number of large boxes

45L + 15(120-L) = 3450

45L + 1800 - 15L = 3450

30L = 1650

L = 1650/30

L = 55 large boxes

 

Questions?

 

s = 120-L = 65 small boxes