Please help you kind people

Show me how you find y and z and determine what y and z are you i appreciate it : )

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.

Find the constant of variation for the relation and use it to write an equation for the statement. then solve the equation.