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 break down the problem step by step.

Given Data:

  • Total number of students: 49
  • Number of men: 11
  • Number of women: 38
  • Number of men who received an A: 2
  • Number of women who received an A: 3

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

The probability P(woman)P(\text{woman}) that the student is a woman is calculated as:

P(woman)=Number of womenTotal number of students=3849P(\text{woman}) = \frac{\text{Number of women}}{\text{Total number of students}} = \frac{38}{49}

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

First, find the total number of students who received an A:

Total number of A’s=Number of men who received an A+Number of women who received an A=2+3=5\text{Total number of A's} = \text{Number of men who received an A} + \text{Number of women who received an A} = 2 + 3 = 5

The probability P(A)P(A) that the student received an A is:

P(A)=Total number of A’sTotal number of students=549P(A) = \frac{\text{Total number of A's}}{\text{Total number of students}} = \frac{5}{49}

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

To find this, we 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(A) - P(\text{woman and A})

We already calculated P(woman)=3849P(\text{woman}) = \frac{38}{49} and P(A)=549P(A) = \frac{5}{49}.

Now, we calculate the probability P(woman and A)P(\text{woman and A}), which is the probability that the student is both a woman and 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, calculate P(woman or A)P(\text{woman or A}):

P(woman or A)=3849+549349=4049P(\text{woman or A}) = \frac{38}{49} + \frac{5}{49} - \frac{3}{49} = \frac{40}{49}

Part (d): Find the 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 received an A:

P(not A)=1P(A)=1549=4449P(\text{not A}) = 1 - P(A) = 1 - \frac{5}{49} = \frac{44}{49}

Final Answers:

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

(b) The probability that the student received an A: 549\frac{5}{49}

(c) The probability that the student is a woman or received an A: 4049\frac{40}{49}

(d) The probability that the student did not receive an A: 4449\frac{44}{49}

Would you like more details on any of these calculations, or do you have any questions?

Here are 5 related questions you might find interesting:

  1. What is the probability that the student is a man?
  2. If a student received an A, what is the probability that they are a woman?
  3. What is the probability that a randomly chosen man did not receive an A?
  4. If you know a student is a woman, what is the probability that she received an A?
  5. What is the probability that a randomly chosen student is a man and did not receive an A?

Tip: Remember, the sum of the probabilities of complementary events (like receiving an A and not receiving an A) is always 1.

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Math Problem Analysis

Mathematical Concepts

Probability

Formulas

Probability of an event = Number of favorable outcomes / Total number of outcomes

Theorems

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Suitable Grade Level

Grades 9-12