A delivery truck is transporting boxes of two sizes: large and small. The large boxes weigh 45 pounds each, and the small boxes weigh 25 pounds each. There are 120 boxes in all. If the truck is carrying a total of 4300 pounds in boxes, how many of each type of box is it carrying?

50(115-y) + 25y = 4125             [from eq2]

    5750 - 50y  + 25y = 4125           [distribute]

    5750 - 25y = 4125

     -25y = -1625

        y = 65             [divide both sides by (-25)]

There are 65 small boxes.

Put that value into either equation (now, which is easier?) to solve for x:

 x = 115 - y

 x = 115 - 65

 x = 50

 There are 50 large boxes.

- Mring0506

i believe it's a.

i'm not sure on this one, most likely correct.