If l is parallel to m, what is the relationship between 3 and 7?

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.

Lola says these two expressions have the same value. expression a expression b which explains whether lola is correct?

Me d is also an option but i couldn't get it in the picture