Mateo Company's average cost per unit is $1.425 at the 16,000 unit level of activity and $1.38 at the 20,000 unit level of activity. Assume that all of the activity levels mentioned in this problem are within the relevant range. Required: Predict the following items for Mateo Company: a. Variable cost per unit. b. Total fixed cost per period. c. Total expected costs at the 18,000 unit level of activity