Vista camera services started the year with total assets of $ 130 comma 000 and total liabilities of $ 60 comma 000 . the revenues and the expenses for the year amounted to $ 100 comma 000 and $ 60 comma 000 , respectively. during the year, the owner did not make any additional contributions, but made withdrawals of $ 40 comma 000 . what is the amount of owner's equity at the end of the year?