a social services worker was comparing other cost incurred by 3families in heati

a social services worker was comparing other cost incurred by 3families in heating their homes for the year. The first family hadan annual heating bill that was $360 more than that of the secondfamily. The third family had a heating bill that was $200 less thandouble the heating bill o the 2nd family. The total central heatingbill for the three families was $3960. What was the annual centralheating bill for all three families?