Probability - choir members getting same copies back
I sing in a men's choir numbering 70. Our librarian gives us each a copy of the sheet music for every song that we are performing, on which we write notes to help us during rehearsals. When we have finished performing a piece of music (this may typically be after a period of 1-2 years) we return the sheet music to the librarian.
When a piece of music comes back into our repertoire, the librarian will randomly hand out copies of the sheet music to choir members.
Assuming the same 70 people are members of our choir (in practice this doesn't happen because membership changes):
1) What is the chance that I will get back the same copy of the sheet music that I handed back last time?
2) What is the chance that at least 1 person in the choir will get back their original copy of sheet music?