Help to solve cost is classified as being semi-variable

Assume the cost and calculate according to the increase or decrease of percentage Activity level : 100 Variable per unit : $2 Fixed : $500 Total : $700 Now do another set which activity level increase by 20% Activity level : 120 Variable per unit : $2 Fixed : $500 Total : $740 Then find the difference in total cost in %

semi variable cost have a fixed part and a variable part. this means semi variable costs rise more sloly than variable costs. therefore the costs will rise but not as fast as 20%