On a recent trip to the convenience​ store, you picked up 3 gallons of​ milk, 4 bottles of​ water, and 8 ​snack-size bags of chips. your total bill​ (before tax) was $19.8. if a bottle of water costs twice as much as a bag of​ chips, and a gallon of milk costs ​$1.60 more than a bottle of​ water, how much does each item​ cost?