Answer:
The ROI is 30%
Explanation:
New contribution margin = old contribution margin + increase
                        = 140.000 + 10.000
                        = 150.000
Net Income = contribution margin – total fixed expense
                = 150.000 -90.000
                = 60.000
ROI= Net income/ average operating assets
        = 60.000/200.000
        =30%