Out of a batch of #60# computers, #5# are damaged. If two computers are chosen at random from the #60#, what is the probability that both are damaged?
1 Answer
Oct 15, 2017
Explanation:
We can suppose that the first and second computers chosen are so distinguished. It does not affect the overall probability.
Then the number of ways of selecting two damaged computers is:
#5 * 4 = 20#
since there are
The total number of ways to choose a first and second computer to test is:
#60 * 59 = 3540#
since there are
So the probability that both chosen computers are damaged is:
#20/3540 = 1/177 ~~ 0.565%#