Can someone help me with question 4:) anything is appreciated (8th grade math)

Mr and mrs smith buy tickets for themselves and their four children. the cost of an adult ticket is ? 6 more than the adult ticket. the total cost of the six tickets is ? 40.50 work out the cost of an adult ticket. in your working let c be the cost of the child ticket and a be the cost of the adult ticket.

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10

What is the radical expression that is equivalent to the expression 27 1 over 5?