Joshua makes $50,000 a year and pays 24% in income tax. Zoe makes $90,000 a year and pays 28% in income tax. What type of tax structure explains this difference?

Flat
Regressive
Progressive
Proportional

The tax structure that explains this difference is progressive. In a progressive tax system, the tax rate increases as income increases. In this case, Zoe, who makes more money, has a higher income tax rate (28%) compared to Joshua, who makes less money and has a lower income tax rate (24%).