Cost During the first  hour, the employees of a machine shop prepare the work area for the...

Cost During the first  hour, the employees of a machine shop prepare the work area for the day’s work. After that, they turn out 10 precision machine parts per hour, so the output after t hours is f(t) machine parts, where f(t) = 10  = 10t − 5,  ≤ t ≤ 8. The total cost of producing x machine parts is C(x) dollars, where C(x) = .1x2 + 25x + 200.

(a) Express the total cost as a (composite) function of t.

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(b) What is the cost of the first 4 hours of operation?