Answer:
A small box weighs 30 lb; a large box weight 60 lb.
Explanation:
Let L = weight of large box
Let S = weight of small box
"The combined weight of a large box and a small box is 90 pounds."
L + S = 90
"The truck is transporting 70 large boxes and 65 small boxes. If the truck is carrying a total of 6150 pounds in boxes"
L = 90 - S Equation 1
The truck carries 65 small boxes and 65 large boxes and another 5 large boxes.
65(90) + 5(90 - S) = 6150 Equation 2
We use these two equations (Eq. 1 and Eq. 2) as a system of equations.
L = 90 - S
5850 + 450 - 5S = 6150
6300 - 5S = 6150
-5S = -150
S = 30
L = 90 - S = 90 - 30 = 60
S = 30; L = 60