3.1 High and Low Method Assuming factory supplies expense is a mixed cost. Based from past annual statistics, the lowest production volume was 80,000 units and the corresponding mixed cost was P280,000 while at its highest production volume of 480,000 units, the mixed cost was P880,000 How much is the: Q18. variable cost rate per unit. Answer is P per unit Q19. total variable cost at 480,000 units. Answer is P Q20. total variable cost at 80,000 units. Answer is P Q21. total fixed costs at 480,000 and at 80,000 units. The answer is P