Answer:
- 1/2
- 3/20
- 1/2
Explanation:
There is an error in the figure. The number "16" shown in the overlap of sets A and B should be "6". "16" is already shown in set A in the part that doesn't overlap set B. (16 cannot be part of set B, as it is not divisible by 3.)
A probability is related to some sort of random process. These sets are well-defined, so there is nothing random about them. Therefore, we interpret the question to mean, "if a number 1-20 were randomly selected, what is the probability it would fall into set ___ ?"
i. There are 10 of the 20 numbers in set A, so P(A) = 10/20 = 1/2.
ii. There are 3 of the 20 numbers in the overlap of sets A and B, so P(A∩B) = 3/20.
iii. The 10 numbers that are not in set A comprise the complement of set A. In any event the probability of a number landing in the complement of set A is 1-P(A) = 1 -1/2 = 1/2.