Find probability

A press release from Gartner indicates that 79.0% of all smartphones sold in the second quarter of 2013 were Android, and 14.2% of all smartphones sold in the second quarter of 2013 were iOS:
If 30 smartphones sold in the second quarter of 2013 are randomly selected:
a) Find the probability that less than 5 are iOS.
b) Find the probability that 20 or 21 are Android.
c) Find the probability that at least 22 are Android.
d) Find the probability that exactly 3 have an operating system that is not iOS and not Android.