<PRE><B>Question 924360</B>
x = number of pen boxes = 15
y = number of pencil boxes = ?
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x + y = 50
15 + y = 50
y = 50 - 15
y = 35
y = number of pencil boxes = 35
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total cost = 3x + 2y
total cost = 3*15 + 2*35
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answer:
total cost = $115
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