jack operates an accounting practice out of the spare bedroom in his 8-room house.This room is jack's principal place of business and it is used exclusively for business purposes.Last year,jack paid $600 for home insurance ,$1400 in utilities ,$2,400 in property tax,$5,600 in mortgage principal and $8,900 in mortgage interest .He does not claim capital cost allowance.How much can jack deduct as a business-use-of-home expense?