Nancy is employed by a large corporation as a sales representative. She is paid a salary of $70,000 during 2015. She is required to have a home office and uses the 375 square foot den in her 1,500 square foot house exclusively for this purpose. Total costs for 2015 were as follows: Mortgage payments (40% principal, 60% interest) $24,000 Home owners insurance 900 Utilities 1,500 Roof repair 800 Property tax 5,000 As Nancys compensation does not include any commissions, she is unable to use some of these costs as tax deductions. If instead, her compensation of $70,000 was in the form of commissions, she would be able to claim extra tax deductions of: