In a cinema, there are rows A-H which each have the same number of seats. At the moment, the cinema seats are quite empty because it is quite early. Only Jack, Jill and a stranger are sitting in the cinema, all on the same row.
Jack looks to the left and sees 6 more seats till the end of the row. He looks to the right and sees 3 seats between him and the stranger. Jill looks to the left and sees 1 seat between her and the stranger. She looks to the right and sees 7 more seats till the other end of the row.
When the cinema is full, how many more people can sit?