In a group of 120 people, 90 have an age of more 30 years

In a group of 120 people, 90 have an age of more 30 years

In a group of 120 people, 90 have an age of more 30 years, and the others have an age of less than 20 years. If a person is selected at random from this group, what is the probability the person's age is less than 20?

Answer:0.25