Flexing budgets

Kaplan Text book, Budgeting, Test your understanding 14

A company manufactures cell phones and has developed a new cell phone called “H”. The max production capacity is 150000 units, management accountant is preparing an annual flexible budget
“000 “000 “000
Production(units) 100 120 150
Mat costs$ 700 840 1050
Lab costs 750 900 1125
Incremental fix costs 60 60 60

What would be the flexed budget total production cost if production cost if production is 90% of maximum capacity?

The only part of this that I didn’t understood how to deal with incremental fixed costs kindly help please