Answer: the cost of one medium sized jug is $60
the cost of one large sized jug is $10
Explanation:
Let x represent the cost of one medium sized jug.
Let y represent the cost of one large sized jug.
Jack bought 2 medium sized jugs and 3 large sized jugs for 150 dollars. This means that
2x + 3y = 150 - - - - - - - - - - - 1
Jill bought 4 medium jugs and 12 large jugs for 360 dollars. This means that
4x + 12y = 360 - - - - - - - - - - - 2
Multiplying equation 1 by 4 and equation 2 by 2, it becomes
8x + 12y = 600
8x + 24y = 720
Subtracting, it becomes
- 12y = - 120
y = - 120/ - 12
y = 10
Substituting y = 10 into equation 1, it becomes
2x + 3 × 10 = 150
2x + 30 = 150
2x = 150 - 30 = 120
x = 120/2 = 60