Bert earns $35,000 gross annual salary. In Bert's jurisdiction there is a progressive tax system with rules as follows: Any amou
nts earned up to $20,000 are taxed at x%. Any amounts earned beyond $20,000 are taxed at 20%. Given that Bert pays $4,500 per annum in income tax, calculate x. Give your answer to the nearest tenth of a percent. Do not include the percent symbol in your answer.
