high low method

sorry Sir It's me again. I have my Cbe in less than 1 week and fell like not ready. another question please: You are going through the cost information of one of the production facility of the company which is as follows: Machine hours Total cost 32,000 515,000 35,000 530,600 41,000 570,000 Variable cost per unit remains unchanged from activity level of 30,000 -40,000 and then from 40,001 to 45,000. What is the total cost if machine runs for 42,500 hours provided: -the fixed cost steps up by 10% if machine hours exceed 36,000 hours -the fixed cost steps down by 10% if machine hours exceed 36,000 hours