The UK currently has a progressive income tax system. The rules are as follows: Any earnings under 11,500 GBP are taxed at 0%. Any earnings between 11,500 GBP and 33,500 GBP are taxed at 20%. Any earnings between 33,500 GBP and 150,000 GBP are taxed at 40%. Any earnings above 150,000 GBP are taxed at 50%. A person earns 50,000 GBP gross. How much tax do they pay? Give your answer in pounds to the nearest pound. Do not include commas or the pound symbol in your answer.