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A student is selected from a class consisting of 10 boys above 20 year
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27 Feb 2022, 12:09
27 Feb 2022, 12:09
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Question Stats:
50% (00:56) correct
50% (01:53) wrong based on 2 sessions
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A student is selected from a class consisting of 10 boys above 20 years of age and 5 boys under 20 years of age and 5 girls above 20 years of age and 10 girls under 20 years of age. What is the probability that a boy above 20 years age is not selected?
A 0.15
B 0.6
C 0.66
D 0.83
A 0.15
B 0.6
C 0.66
D 0.83
Re: A student is selected from a class consisting of 10 boys above 20 year
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27 Feb 2022, 12:22
27 Feb 2022, 12:22
2
take the probability of the event not occurring over all possibilities. So, 20 children who are not boys above the age of 20 over 30 total children. 20/30=.66667
Re: A student is selected from a class consisting of 10 boys above 20 year
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27 Feb 2022, 12:35
27 Feb 2022, 12:35
3
Expert Reply
Another way of solving this question is to focus on the complement of the event. This will reduce the number of events we need to focus upon.
P[Boy Above 20 years is not selected]= 1- P[Boy Above 20 years is selected]
\(= 1- \frac{10}{30}\)
\(=1-0.333\)
\(=0.667\)
Hence, the answer is C.
P[Boy Above 20 years is not selected]= 1- P[Boy Above 20 years is selected]
\(= 1- \frac{10}{30}\)
\(=1-0.333\)
\(=0.667\)
Hence, the answer is C.
