Answer and Explanation:
Natalie's Gross Income = $10,000 
75 + 35 = 110 days 
Expenses: 
Insurance Expense (75/110) x 1000                 682
Advertising Expense                                        500
Mortgage Interest (75/110) x 3500                  2386
Property Taxes (75/110) x 900                         614
Repairs and Maintenance (75/110) x 650        443
Utilities    (75/110) x 950                                   648
Depreciation (75/110) x 8500                          5795 
Until the depreciation expenses the total expenses accumulate to  5273. If we deduct that with the gross income total we get 4727. We can only deduct 4727 from the total portion of 5795 depreciation expense. 
Therefore, for AGI deductions we take total of (5273 + 4727) = $10,000
For Natalie's personal deduction of AGI 
Mortgage interest (35/110) x 3500                    1114
Property taxes (35/110) x 900                            286
Total personal deduction for AGI                    $1400