Question

A supply company manufactures copy machines. The unit cost C (the cost in dollars to make each copy machine) depends on the number of machines made. If

x machines are made, then the unit cost is given by the function C(x) -0.4x-112x+17,167. What is the minimum unit cost? I got the answer $140 but apparently it was wrong.

Answer 1

$9327

Explanation:

Apparently, the cost function is supposed to be ...

C(x) = 0.4x^2 -112x +17167

This can be rewritten to vertex form as ...

C(x) = 0.4(x^2 -280) +17167

C(x) = 0.4(x -140)^2 +17167 -0.4(19600)

C(x) = 0.4(x -140)^2 +9327

The vertex of the cost function is ...

(x, C(x)) = (140, 9327)

The minimum unit cost is $9327.

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Comment on the question

You found the number of units that result in minimum cost (140 units), but you have to evaluate C(140) to find the minimum unit cost.