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.

The cost of an adult ticket is £6 more than that of a child ticket, so will be denoted by c+6. Now, we are told that the cost of four child tickets and two adult tickets is £40.50, so we can put this in an equation and solve for c:
(c+6)+(c+6)+c+c+c+c=40.50
6c+12=40.50
6c=28.50
c=4.75
Therefore the cost of a child's ticket (c) is £4.75 and the cost of an adult ticket (c+6) is £10.75.