Question 177423
Suppose the monthly cost of a long distance phone plan (in dollars) is a linear function of the total calling time(in minutes). When graphed, the function gives a line with a slope og 0.12. The monthly cost for 41 minutes is 18.73. What is the monthly cost for 48 minutes?
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cost = slope*(minutes) = intercept
slope = 0.12 and you have the pair (41,18.73)
Substitute the pair into the equation to solve for the intercept value:
18.73 = 0.12*41 + intercept
intercept = 18.73 - 4.92
intercept = 13.81
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Equation:
C(x) = 0.12x + 13.81
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Cheers,
Stan H.