The function f(x) gives the income tax paid on x dollars of taxable income: f(x) = 0.20x if 0 ≤ x ≤ 15000, 0.25(x - 15000) + 3000 if 15000 ≤ x ≤ 45000, 0.35(x - 45000) + 10500 if x > 45000. Find the income tax paid when the taxable income is $42500.