Question 409767
 I have a lemonade stand and charged $1.00 per cup and sold 48 cups. When I raised the price to $2.00 per cup I only sold 27 cups. I need to write an equation for the number of cups I sold as a function of the price I charged. "C" would be for the number of cups and "P" would denote the price I charged.
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You have two points (1,48) and (2,27)
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slope = (48-27)/(1-2) = -21
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Form: C = mP + b
Substitute and solve for "b":
48 = -21(1)+b
b = 69
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Equation:
C(P) = -21P + 69
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Cheers,
Stan H.
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