Step 1 :Calculate Rajesh's taxable income by subtracting the standard deduction from his adjusted gross income (AGI). The formula is \(\text{Taxable income} = \text{AGI} - \text{Standard deduction}\). Substituting the given values, we get \(\text{Taxable income} = $94,000 - $12,000 = $82,000\).
Step 2 :Next, calculate his tax based on the tax rate schedule. His taxable income falls into the third bracket ($38,700 to $82,500), so his tax is calculated as follows: \(\text{Tax} = $4,453.50 + 22\% \text{ of the excess over } $38,700\). Substituting the given values, we get \(\text{Tax} = $4,453.50 + 22\% * ($82,000 - $38,700) = $4,453.50 + 22\% * $43,300 = $4,453.50 + $9,526 = $13,979.50\). Rounding to the nearest dollar, Rajesh's 2018 tax is \(\boxed{$13,980}\).
Step 3 :Finally, calculate Rajesh's effective tax rate by dividing the tax paid by his taxable income and multiplying by 100 to get a percentage. The formula is \(\text{Effective tax rate} = (\text{Tax paid} / \text{Taxable income}) * 100\). Substituting the given values, we get \(\text{Effective tax rate} = ($13,980 / $82,000) * 100 = 17.04878\%\). Rounding to one decimal place, Rajesh's effective tax rate is \(\boxed{17.0\%}\).