



 
Ben, I see this graphically so I began with a rough sketch of minutes against dollars. The graph is a flat line until the time reaches 100 minutes and then it increases at a slope of 0.10 dollars/minute. At 500 minutes the slope of the line decreases to 0.05 dollars/minute. This is sometimes called a piecewise function. The graph is in three pieces so I would write the function in 3 pieces. where c is the cost in dollars and t is the time in minutes. f(t) is the constant function f(t) = 50. g(t) is the line with slope 0.10 and passing through (100, 50). I got g(t) = 0.10t + 40. You can find h(t) and then the function is Penny  


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