Question

A fruit company delivers its fruit in two types of boxes: large and small. A delivery of

3
large boxes and
5
small boxes has a total weight of
90
kilograms. A delivery of
9
large boxes and
7
small boxes has a total weight of
216
kilograms. How much does each type of box weigh?

Answer 1

3L + 5S = 90.....multiply by -3
9L + 7S = 215
-------------------
-9L - 15S = -270 (result of multiplying by -3)
9L + 7S = 216
-------------------add
- 8S = - 54
S = 54/8 = 6 3/4 or 6.75 kg (for the small boxes) <===

3L + 5S = 90
3L + 5(6.75) = 90
3L + 33.75 = 90
3L = 90 - 33.75
3L = 56.25
L = 56.25/3
L = 18 3/4 or 18.75 kg (for the large boxes) <===