Question

A delivery truck is transporting boxes of two sizes: large and small. The combined weight of a large box and a small box is 70 pounds. The truck is transporting 50 large boxes and 60 small boxes. If the truck is carrying a total of 3800 pounds in boxes, how much does each type of box weigh?

Answer 1

Answer: Large box weight 40 pounds, and small box weight 30 pounds.

Explanation:

Let L be the weight of a large box, and S be the weight of a small box.

L + S = 70

50L + 60S = 3800

We change the first equation into the form of L, and we get:

L = 70 - S

And we plugin L = 70 - S into the second equation.

50(70 - S) + 60S = 3800

3500 - 50S + 60S = 3800

3500 + 10S = 3800

-3500 -3500

10S = 300

S = 30

L + S = 70

L + 30 = 70

- 30 - 30

L = 40