How many times does 8 go in 400

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.

Order the measurements from the least to the greatest. 2,720 ml , 24.91 l , 0.0268 kl

Ithink i know it but i want to be sure so can you me out ?