For earnings less than 90,000 per annum, the tax is 5% on those earnings. This makes the maximum tax 4,500.
Over 90,000 and up to 140,000, the tax rate increases to 15% on the earnings above 90,000 plus the maximum of 4,500 on the first 90,000. The maximum is 0.15*50,000 (140,000-90,000=50,000)=7,500+4,500=12,000.
Over 140,000 and up to 220,000, the tax increases to 25% on earnings above 140,000 plus the tax accumulated at the lower rates, 12,000. The maximum is 0.35*80,000=28,000 (220,000-140,000=80,000) plus 12,000=40,000.
Over 220,000, the tax is 35% on earnings above 220,000 plus 32,000, rather than the 40,000 accumulated at lower rates. There is no maximum upper limit.