OG详解-OG9 数学2 Q3

Choice D is correct. If a member of the organization is selected at random, the probability that the selected member is at least 40 years old is equal to the number of members who are at least 40 years old divided by the total number of members. According to the table, there area total of 135 members of the organization, and 107 of these members are at least 40 years old. Therefore, the probability that the selected member is at least 40 years old is 107135​​.
Choice A is incorrect. This is the probability that the selected member is less than 40 years old. Choice B is incorrect. This is the probability that the selected member lives east of the river. Choice C is incorrect. This is the probability that the selected member lives west of the river.