Arrows. An Olympic archer is able to hit the bull s-eye 80% of the time. Assume each shot is independent of the others. If she shoots 6 arrows, what's the probability of each of the following results?
a) Her first bull s-eye comes on the third arrow.
b) She misses the bull s-eye at least once.
c) Her first bull s-eye comes on the fourth or fifth arrow.
d) She gets exactly 4 bull s-eyes.
e) She gets at least 4 bull s-eyes.
f) She gets at most 4 bull s-eyes.