Answer:
C = 9x -600
Step-by-step explanation:
When the number of parts produced goes up by 500 from 100 to 600, the cost goes up $4500 from 300 to 4800. Thus the average cost of producing a part is $4500/500 = $9.
If that were the total cost of producing a part, then the first 100 parts would cost $9×100 = $900. They only cost $300, so $600 must be subtracted from the value 9x to get the cost.
... C = 9x -600
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Check
100 parts cost 9·100 -600 = 300 . . . agrees with problem statement
600 parts cost 9·600 -600 = 4800 . . . agrees with problem statement
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Comment on the problem statement
The initial statement tells you "cost ... related to the quantity produced." The question then asks you to "find an equation ... relating quantity produced to cost." The latter statement suggests you want the independent variable to be cost, not quantity. Here, we have made quantity be the independent variable, as suggested by the use of C= in the answer form.
