Calculus
posted by Jose .
A manufacturer sells a certain article to dealers at a rate of $20 each if less than 50 are ordered. If 50 or more are ordered(up to 600) the price per article is reduced at a rate of 2 cents times the number ordered. What size order will produce the maximum amount of money for the manufacturer?

I think I am reading this wrong but this may not be a Calculus question.
<= means less than or equal to
>= means greater than or equal to
Rates
20*x 0 < x < 50
200.02*x 50 <= x <= 600
When buying 149 articles, it is $20 per article.
When buying 50600 articles, it is $(20.02*x).
As you buy more, the cheaper it gets until you reach 600, then it maintains at that cost which is $8 dollars per article.