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09 Jan 2025, 01:30
Kudos
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E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
55%
(hard)
Question Stats:
68% (02:18) correct
32%
(02:07)
wrong
based on 175
sessions
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Not Attempted Yet
Each of the 30 students in a class is either male or female, and has blonde, brown, or red hair. If one student is to be randomly selected from the class, what is the probability that the student will either be female or have brown hair?
(1) The probability that the student will be both female and have brown hair is 0.1
(2) The probability that the student will be female minus the probability that the student will have brown hair is 0.25
(1) The probability that the student will be both female and have brown hair is 0.1
(2) The probability that the student will be female minus the probability that the student will have brown hair is 0.25
11 Jan 2025, 13:39
Kudos
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Bunuel
We need to find p(female or brown) = p(female) + p(brown) - p(both)
We can use a table to solve:
_______Blonde______Brown________Red________Total
Men
Women
Total
S1: Probability of female having brown hair = 0.1 => Number of people who are female with brown hair = 0.1 * 30 = 3
But we have noi information about p(brown) and p(female) - Insufficient
S2: p(female) - p(brown) = 0.25 - Insufficient since we need p(female) + p(brown) - Insufficient
Ans E
17 Jan 2025, 11:31
Kudos
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Bunuel
P(F ∪ B) = P(F) + P(B) - P(F ∩ B)
P(F ∪ B)?
Statement 1 => P(F ∩ B) = 0.1
Not sufficient
Statement 2 => P(F) - P(B) = 0.25
Not sufficient
Taking both together, we know, P(F) - P(B) - P(F ∩ B), but we need to calculate P(F) + P(B) - P(F ∩ B), hence not sufficient.
IMO: E
