Answer:
Depends on the pool you are pulling them from.
There are currently 11 different denomination accessible.
That would be 1 out of 11.
But considering that 4 of those bills are uncommon, the odds become 1 out of 7
Then to pull 2 of the same would mean you multiply 1/11 by 1/11 = 1/121
for the 1/7 it would become 1/49