As per Canada.

(Ontario)

The following data represents the complete taxable income history for a firm: Taxable Income Tax Rate 20x1 $20,000 0.30 20x2 $16,000 0.30 20x3 $12,000 0.35 20x4 $4,000 0.40 20x5 0.40 $(40,000) $20,000 20x6 0.45 What is the tax liability for 2016