Question 1177357
21 were orchestra alone, leaving 17.
7 were piano
5 violin
7 chorus.
this adds to 40, so there have to be two doubling up
one is piano and violin.
the other has to be either violin and chorus, but that is 0, or piano and chorus, which has to be 1.  All three was not mentioned, so assume that is 0.

5 were piano alone
1 was piano and violin
4 were violin
6 chorus
1 piano and chorus
-
So the answer yes and 1.


The last four add to 17, accounting for all 38,
There can be no piano and chorus together.