SOLUTION: In a class of 25 students, 80% are passing the class with a grade of C or better. If two students are randomly selected from the class, what is the probability that neither student

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: In a class of 25 students, 80% are passing the class with a grade of C or better. If two students are randomly selected from the class, what is the probability that neither student      Log On


   



Question 1189617: In a class of 25 students, 80% are passing the class with a grade of C or better. If two students are randomly selected from the class, what is the probability that neither student is passing with a grade of C or better?
A)0.03 B)0.20 C)0.08 D)0.63 E)0.64

Answer by ikleyn(52790) About Me  (Show Source):
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In a class of 25 students, 80% are passing the class with a grade of C or better.
If two students are randomly selected from the class, what is the probability
that neither student is passing with a grade of C or better?
A)0.03 B)0.20 C)0.08 D)0.63 E)0.64
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80% of 25 is 20 students.


So, 20 students are passing the class with a grade of C or better,

and 5 students are passing the class with the lower grade.


Therefore, the probability under the problem's question is


    P = %285%2F25%29%2A%284%2F24%29 = %281%2F5%29%2A%281%2F6%29 = 1%2F30.    ANSWER

Solved.

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The formula for P is SELF-EXPLANATORY.