Mary's salary is $X per annum. The tax system is such that Mary pays a 15% flat rate of income tax on her salary. The tax system is due for reform, and politicians have suggested the following: Any income under $7,500 should be tax free.
Any income above $7,500 should be taxed at 25% on the amount over $7,500.
Given that Mary will be paying exactly the same amount of tax under both systems, calculate the amount of tax that Mary pays. Give your answer in dollars and cents to the nearest cent. Do not include commas or the dollar symbol in your answer.