USA Quiz confusing question

[Amel]

buildings , july 31, 2021, unadjusted balance 243000 . the company owns a building purchased on Sep 01, 2017. for 243000 with an estimated 30 year useful life. the company uses straight line depreciation . how much is the annual depreciation expense for the building .
How much should the adjusted balance in the accumulated depreciation buildings account be at Jul 31, 2021

 

[Amel]

I got it , 8,100.00