We want to know the probability of a passenger to be younger than 30.
There are 10 persons on the bus and out of those, just 2 are younger than 30.
Denote by E the event: "obtaining a person younger than 30 when its selected at random from the bus". Then,
[tex]P(E)=\frac{\text{number of persons younger than 30}}{\text{total persons on the bus}}=\frac{2}{10}=\frac{1}{5}=0.2[/tex]This means that the probability of a passenger to be younger than 30 is 0.2.
