Question

In a group of 25 factory workers, 20 are low-risk and five are high-risk. two of the 25 factory workers are randomly selected without replacement. calculate the probability that exactly one of the two selected factory workers is low-risk.

Answer 1

Let
L=event that a selected worker has low risk
H=event that a selected worker has high risk

We need to find
P(HL)+P(LH)
=5*20/(25*24)+20*5/(25*24)
=1/6+1/6
=1/3