Answer =
Equations:
Quantity Eq. : h + c = 375
Quantity Eq. : c = 3h
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Substitute to solve for "h":
h + 2h = 375
3h = 375
h = 125 (# of hamburgers)
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Substitute to solve for "c":
125 + c = 375
c = 250 (# of cheeseburgers)