Question

There are 6 cans of juice of the same weight and a box. If the 6 cans

are put in the box, the total weight of the cans and the box is 1620 g.
If only 2 cans are put in the box, the total weight is 660g. How many
grams does this box weigh?

Answer 1

The answer would be: each individual can weighs 240g and the box weighs 180g
Here are the steps:

1) first we take the 2 equations we made and line them up
6c+b=1620
2c+b=660

2) next we would subtract the equations from each other to cancel out b
6c+b=1620
- 2c +b=660
=. 4c=960

3) then we divide 960 by 4 to get c alone
960/4=240
That means that one can would weight 240g

4) we substitute 240 in for c to solve for b
2(240)+b=660 (times 240 by 2)
480+b=660 (subtract 480 from both sides)
B=180
That means the box would weight 180g