Math Problem Statement

Statistics grades: In a statistics class of 

49

 students, there were 

11

 men and 

38

 women. Two of the men and three of the women received an A in the course. A student is chosen at random from the class.

(a) Find the probability that the student is a woman.

(b) Find the probability that the student received an A.

(c) Find the probability that the student is a woman or received an A.

(d) Find the probability that the student did not receive an A.

Solution

Let's solve each part of the problem step by step.

(a) Probability that the student is a woman

The total number of students is 4949, and the number of women is 3838.

The probability that the student is a woman is given by: P(Woman)=Number of womenTotal number of students=3849P(\text{Woman}) = \frac{\text{Number of women}}{\text{Total number of students}} = \frac{38}{49}

(b) Probability that the student received an A

The total number of students who received an A is the sum of the men and women who received an A: Number of students who received an A=2(men)+3(women)=5\text{Number of students who received an A} = 2 (\text{men}) + 3 (\text{women}) = 5

The probability that the student received an A is: P(A)=Number of students who received an ATotal number of students=549P(\text{A}) = \frac{\text{Number of students who received an A}}{\text{Total number of students}} = \frac{5}{49}

(c) Probability that the student is a woman or received an A

To find this probability, we need to use the formula for the union of two events: P(Woman or A)=P(Woman)+P(A)P(Woman and A)P(\text{Woman or A}) = P(\text{Woman}) + P(\text{A}) - P(\text{Woman and A})

First, we calculate P(Woman and A)P(\text{Woman and A}), which is the probability that the student is a woman who received an A: P(Woman and A)=Number of women who received an ATotal number of students=349P(\text{Woman and A}) = \frac{\text{Number of women who received an A}}{\text{Total number of students}} = \frac{3}{49}

Now, substituting the values: P(Woman or A)=3849+549349=4049P(\text{Woman or A}) = \frac{38}{49} + \frac{5}{49} - \frac{3}{49} = \frac{40}{49}

(d) Probability that the student did not receive an A

The probability that the student did not receive an A is the complement of the probability that the student did receive an A: P(Not A)=1P(A)=1549=4449P(\text{Not A}) = 1 - P(\text{A}) = 1 - \frac{5}{49} = \frac{44}{49}

Summary of Probabilities

  • (a) Probability that the student is a woman: 3849\frac{38}{49}

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Math Problem Analysis

Mathematical Concepts

Probability
Combinatorics

Formulas

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Theorems

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Suitable Grade Level

Grades 10-12