Math Problem Statement

A university is putting together a hiring committee of 6 members for the next university provost. The eligible pool of members consists of 4 administrative personnel, 9 faculty, and 10 students. Suppose the committee is chosen at random and with no restrictions. What is the probability that each subgroup has 2 members on the committee? Express your answer as a decimal rounded to the nearest millionth.

Solution

To solve this problem, we use combinations and the basic principles of probability.

Step 1: Understand the problem

We are forming a committee of 66 members. The eligible pool contains:

  • 44 administrative personnel,
  • 99 faculty,
  • 1010 students.

We are tasked with finding the probability that the committee contains exactly 22 administrative personnel, 22 faculty, and 22 students.

Step 2: Total ways to choose the committee

The total pool of eligible members is: 4+9+10=23.4 + 9 + 10 = 23. The total number of ways to choose 66 members from 2323 is: (236)=23×22×21×20×19×186×5×4×3×2×1=100947.\binom{23}{6} = \frac{23 \times 22 \times 21 \times 20 \times 19 \times 18}{6 \times 5 \times 4 \times 3 \times 2 \times 1} = 100947.

Step 3: Ways to select the specific composition

We want exactly 22 administrative personnel, 22 faculty, and 22 students. For each subgroup:

  • The number of ways to choose 22 administrative personnel from 44 is: (42)=4×32×1=6.\binom{4}{2} = \frac{4 \times 3}{2 \times 1} = 6.
  • The number of ways to choose 22 faculty from 99 is: (92)=9×82×1=36.\binom{9}{2} = \frac{9 \times 8}{2 \times 1} = 36.
  • The number of ways to choose 22 students from 1010 is: (102)=10×92×1=45.\binom{10}{2} = \frac{10 \times 9}{2 \times 1} = 45.

The total number of ways to select 22 administrative personnel, 22 faculty, and 22 students is: 6×36×45=9720.6 \times 36 \times 45 = 9720.

Step 4: Calculate the probability

The probability is the number of favorable outcomes divided by the total outcomes: P=9720100947.P = \frac{9720}{100947}.

Step 5: Simplify and round

Performing the division: P0.09634.P \approx 0.09634.

Final Answer:

The probability that the committee contains 22 members from each subgroup is approximately: 0.096340.\boxed{0.096340}.

Would you like further explanation or to explore related questions?


Related Questions:

  1. What if the committee required 33 faculty, 22 students, and 11 administrative personnel?
  2. What is the probability that there are no administrative personnel on the committee?
  3. How many total committees can be formed with at least one member from each group?
  4. What is the expected number of students in a randomly chosen committee of 66?
  5. If the committee required a majority of students, what is the probability of forming such a committee?

Tip:

When calculating probabilities involving combinations, ensure that all restrictions (like specific subgroup counts)

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Math Problem Analysis

Mathematical Concepts

Combinatorics
Probability

Formulas

Combination formula: C(n, r) = n! / (r!(n - r)!)
Probability formula: P = Favorable Outcomes / Total Outcomes

Theorems

Basic Probability Principles
Counting Principle

Suitable Grade Level

Grades 10-12