Answer:
depends on the tempo (3 over 4, 2 over 4, 4 over 4). Easy answer is in a 4 over 4 tempo,
a whole note receives 4 counts (the whole measure),
a half note receives 2 counts,
a quarter note receives 1 count (or beat) (see the pattern?),
and watch this: half of a quarter is an eighth (music) so an eighth note receives half a count.
test to you: how many counts does a sixteenth note receive?.