There are 15600 different possible choices of voicemail passwords.
What is a permutation?
A permutation is defined as a mathematical process which determines the number of different arrangements in a set of objects when the order of the sequential arrangements.
According to the fundamental counting principle, there are 26 choices of letters and 600 different digits of numbers,
So, the Count of possibilities as
⇒ 26 x 600
⇒ 15600
Hence, there are 15600 different possible choices of voicemail passwords.