In a group of 100 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?
Choose the correct choice.
A) 0.1 B) 0.55 C) 0.65 D) 0.75 E) 0.85

Rationale: number of people whose age is less than 20 is given by 100 - 90 = 10 probability p that a person selected at random from the group is less than 20 is given by 10 / 100 = 0.1 correct answer a
Answer: A