Since the tutors on here often speak about the clarity of the problems posted
here, I thought I'd mention this one.

What is meant by the word "patron"?  I think a patron is ONE individual person,
not to be considered as, say, TEN DIFFERENT patrons if he or she attends TEN
different performances.

I claim the problem is not clear, and the answer could range between 
10000-256=9744 patrons and 10000-9728=272 patrons.

It's theoretically possible that there were only 256 patrons and all 256 of
those same patrons attended all 38 performances.

On the other end, it's theoretically possible there were 38*256=9728 different
patrons and each attended exactly 1 performance each.

If the answer is really 9728, then the problem should be worded so that it would
be clear that if the same person attends two or more performances, then she or
he would be counted as many times as she or he attended one of the 38
performances.

Another way to clearly word it would be to speak of the number of tickets sold
instead of the number of patrons.

Edwin