The following data pertains to activity and costs for two months: June July Activity level in units. 10,000 20,000 Variable cost.. $20,000 S ? Fixed cost 15,000 Mixed cost.. 10,000 Total cost. $45.000 $70.000 Assuming that these activity levels are within the relevant range, the mixed cost for July was: $10,000 $35,000 $15,000 as $40,000