One day, Alison notices that her cinema is full, and she has taken exactly £100.
The prices were as follows:
She knows that not everyone in the audience was a pensioner!
How many adults, pensioners and children were present?
You may want to pick some combinations to start off with, and then tweak them to get closer to the answer.
This spreadsheet might help.
Once you've explored this, you might like to take a look at Cinema Surprises.