algebra
posted by sally .
A family of 2 adults and 4 children visited Sentosa during the June holidays.An adult ticket cost $18.90 and a child ticket $12.80 during the promotional period.if the family enjoyed the promotional price,what was the total cost of the tickets for the family ?and what would be the change if a $100note was used to purchase the tickets ?

100  (2*18.90 + 4*12.80)