A shelf in the Metro Department Store contains 85 colored ink cartridges for a popular ink-jet printer. Five of these cartridges are defective.
a) If a customer selects 2 of these cartridges at random from a shelf, what is the probability that they are all defective?
(b) If a customer selects 2 of these cartridges at random from a shelf, what is the probability that at least 1 is defective?