Use the 2010 Federal Income Tax Brackets and Rates Listed

Use the 2010 federal income tax brackets and rates listed below to answer the following question.
Taxable Income
(income tax brackets) Tax rates
$40 970 or less 5% of taxable income less than or equal to $40 970; plus
$40 970 to $81 94 22% of taxable income greater than $40 970 and less than or equal to $91 941; plus
$81 941 to $127 021 26% of taxable income greater than $81 941 and less than or equal to $127 021; plus
Over $127 021 29% of taxable income greater than $127 021
a) Sean had a taxable income of $42 500 in 2011. How much federal income tax should he report? (assuming tax rates remain the same)
b) Sean expects his taxable income to increase by 150% in 2012. How much federal tax would he expect to pay in 2012(assuming tax rates remain the same).