SAT question 2905ded0 (Probability And Conditional Probability)

Question

The table summarizes members of a local organization by age and whether they live east or west of the river. If a member of the organization is selected at random, what is the probability that the selected member is at least 40 years old?

College Board · Accepted Answer

The correct answer is D. 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 are a 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 (107)/(135) .

CookSAT · Answer

Note: The fraction 107/135 is entered directly from the table the numerator is the total for “at least 40 years old” and the denominator is the grand total.

	Live east of the river	Live west of the river	Total
Less than $40$ years old	$17$	$11$	$28$
At least $40$ years old	$18$	$89$	$107$
Total	$35$	$100$	$135$

Explanation

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Why the other choices are wrong

SAT Question 2905ded0: Probability And Conditional Probability answer and explanation with Desmos solution

Explanation

Enter in Desmos:

Why the other choices are wrong