Ineed to know how to figure out what x is and what y is

Atotal of 766 tickets were sold for the school play. they were either adult tickets or student tickets. there were 66 more student tickets sold than adult tickets. how many adult tickets were sold?

Asalsa recipe uses green pepper, onion, and tomato in the extended ratio 3: 5: 7. how many cups of tomato are needed to make 105 cups of salsa? a. 7 b. 21 c. 35 d. 49

15 oranges weigh 3.75 kilograms (kg). if each orange weighs approximately the same, approximately how much does each orange weigh?