A certain class has $45$ students. If a student is picked at random, the probability of picking a prefect is $\frac{1}{3}$ . How many students in the class are not prefects?

60

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15

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30

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70

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Solution

The correct option is C $30$
A certain class has 45 students. If a student is picked at random, the probability of picking a prefect is $\frac{1}{3}$ .
Total number of prefects are $total=P(E)student= $\frac{1}{3} 45$
therefore the number of students who are not prefects are $45 - 15 = 30$

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A certain class has 45 students. If a student is picked at random, the probability of picking a prefect is 13. How many students in the class are not prefects?

The correct option is C 30A certain class has 45 students. If a student is picked at random, the probability of picking a prefect is 13.Total number of prefects are $total=P(E)*student=13∗45therefore the number of students who are not prefects are 45−15=30

A certain class has $45$ students. If a student is picked at random, the probability of picking a prefect is $\frac{1}{3}$ . How many students in the class are not prefects?

The correct option is C $30$
A certain class has 45 students. If a student is picked at random, the probability of picking a prefect is $\frac{1}{3}$ .
Total number of prefects are $total=P(E)student= $\frac{1}{3} 45$
therefore the number of students who are not prefects are $45 - 15 = 30$