The big screen
y = 12.9x
For 6 y = 12.9(6)
y = $77.4
Perfect picture tickets
$65.5 for 5-tickets
then, for one ticket
65.5 / 5 = 13.1
$65.5 + $13.1
$78.6
Graph
For 6 tickets the cost is $81
So the cheapest tickets are from The big screen, so it is the best deal.