Problem
A certain state uses the following progressive tax rate for calculating individual income tax: \begin{tabular}{c|c} \( \begin{array}{c}\text { Income } \\ \text { Range }(\$)\end{array} \) & \( \begin{array}{c}\text { Progressive } \\ \text { Tax Rate }\end{array} \) \\ \hline \( 0-10,000 \) & \( 3 \% \) \\ \( 10,001-50,000 \) & \( 5 \% \) \\ \( 50,001-100,000 \) & \( 5.5 \% \) \end{tabular} Calculate the state income tax owed on a \( \$ 90,000 \) per year salary. \[ \operatorname{tax}=\$[?] \]
Solution
Step 1 ：1. Calculate tax for income range \(0-10,000\): \(10,000 * 0.03\) = \(300\)
Step 2 ：2. Calculate tax for income range \(10,001-50,000\): \((50,000 - 10,000) * 0.05\) = \(40,000 * 0.05\) = \(2,000\)
Step 3 ：3. Calculate tax for income range \(50,001-90,000\): \((90,000 - 50,000) * 0.055\) = \(40,000 * 0.055\) = \(2,200\)
Step 4 ：4. Add all taxes: \(300 + 2,000 + 2,200\) = \(4,500\)
