A bag contains a total of 20 batteries, of which four are defective. Selecting two at random, without replacement, determine the probability that none of the batteries you select are good.
The sample set is the ways to choose any 2 out of the 20, or
These:
16 good ones, choose 2, or 16C2,
out of these:
20 batteries choose 2 or 20C2
Answer:
Edwin