Answer: the cost of one box of envelope is $3.75.
the cost of one box of notebook paper is $2.85
Step-by-step explanation:
Let x represent the cost of one box of envelope.
Let y represent the cost of one box of notebook paper.
The cost of 3 boxes of envelopes and 4 boxes of notebook paper is $22.65. This means that
3x + 4y = 22.65 - - - - - - - - - - -1
Two boxes of envelopes and 6 boxes of notebook paper cost $24.60. This means that
2x + 6y = 24.6 - - - - - - - - - - -2
Multiplying equation 1 by 2 and equation 2 by 3, it becomes
6x + 8y = 45.3
6x + 18y = 73.8
Subtracting, it becomes
- 10y = - 28.5
y = - 28.5/-10
y = 2.85
Substituting y = 2.85 into equation 1, it becomes
3x + 4 × 2.85 = 22.65
3x + 11.4 = 22.65
3x = 22.65 - 11.4 = 11.25
x = 11.25/3 = 3.75
