A review of the ledger of Coronado Corporation at its year end, July 31, 2021, produces the following unadjusted data for the preparation of annual adjusting entries: 1. Prepaid Insurance, July 31, 2021, unadjusted balance, $10,080: The company purchased an insurance policy on December 1, 2019, with a two-year term, which expires November 30, 2021. 2. 3. 4. Buildings, July 31, 2021, unadjusted balance, $234,000: The company owns a building purchased on September 1, 2017, for $234,000, with an estimated 30-year useful life. The company uses straight-line depreciation. Deferred Revenue, July 31, 2021, unadjusted balance, $46,750: The selling price of a digital magazine subscription is $66 for 24 monthly issues delivered over a two-year period. The company had sold 1,000 subscriptions on January 1, 2020, during a special promotion. Salaries Payable, July 31, 2021, unadjusted balance, $0: There are 9 salaried employees. Salaries are paid every Monday for the previous five-day workweek (Monday to Friday). 6 employees receive a salary of $610 each per week, and 3 employees earn $720 each per week. July 31 is a Saturday. (a1) How much insurance expires per month for the building? Insurance expires per month (a3) What was the original purchase price of the policy on December 1, 2019? Original purchase price of the policy $ (a4) How much should the adjusted balance in the Prepaid Insurance account be at July 31, 2021? Adjusted balance in the Prepaid Insurance account (b1) How much is annual depreciation expense for the building? Annual depreciation expense