Acompany that makes replacement car parts has a fixed cost of $3,000 per month and a variable cost of $15 per part. if each part is sold at $25, the company has to sell a minimum of
parts to break even.

The breakeven of a certain event is when the amount of cost is equal to the amount gained from the sales. The total cost of producing x car parts is equal to the sum of the fixed cost ($3,000) and the variable cost ($15 per part). This cost should be equal to the revenue when selling the parts for $25 each.
  
                                   3,000 + 15x = 25x

The value of x from the equation is 300. 
Thus, the company should sell a minimum of 300 car parts in order to breakeven.