This was a partial discssion of a problem solve din class today - a problem with insufficient (and useless) information.

Alice, Bob and Cheryl form a line to buy tickets.
The shortest is not first an the tallest is not last.
The boy is not the oldest and the youngest is a girl.
The oldest is not first in the line.

What are their positions in the line?

If there is no definite answer, are you able to work out all the possibilities?