Math Problem Statement

A committee of 6 U.S. senators is to be formed with 3 Democrats and 3 Republicans. In how many ways can this be done if there are 69 Democratic senators and 31 Republican senators?

Solution

We are tasked with forming a committee of 6 U.S. senators that consists of 3 Democrats and 3 Republicans. There are 69 Democratic senators and 31 Republican senators to choose from.

Step 1: Choosing 3 Democrats

From the 69 Democratic senators, we need to select 3. The number of ways to choose 3 Democrats from 69 can be calculated using the combination formula:

(nr)=n!r!(nr)!\binom{n}{r} = \frac{n!}{r!(n-r)!}

So, the number of ways to choose 3 Democrats from 69 is:

(693)=69×68×673×2×1=52394\binom{69}{3} = \frac{69 \times 68 \times 67}{3 \times 2 \times 1} = 52394

Step 2: Choosing 3 Republicans

Similarly, we need to choose 3 Republicans from the 31 Republican senators. The number of ways to choose 3 Republicans from 31 is:

(313)=31×30×293×2×1=4495\binom{31}{3} = \frac{31 \times 30 \times 29}{3 \times 2 \times 1} = 4495

Step 3: Calculating the Total Number of Ways

To form the committee, we need to select both 3 Democrats and 3 Republicans. Since the selections are independent, the total number of ways to form the committee is the product of the two combinations:

Total number of ways=(693)×(313)=52394×4495=235,872,730\text{Total number of ways} = \binom{69}{3} \times \binom{31}{3} = 52394 \times 4495 = 235,872,730

Thus, the total number of ways to form the committee is:

235,872,730\boxed{235,872,730}

Would you like more details, or do you have any questions?

Here are 5 related questions to expand this topic:

  1. How would the result change if we needed to select 4 Democrats and 2 Republicans instead?
  2. What if there were only 60 Democratic senators? How would that affect the outcome?
  3. Can you find the probability that a randomly chosen committee has exactly 3 Democrats and 3 Republicans?
  4. How would the problem change if each party had the same number of senators (say, 50 each)?
  5. In how many ways can we form a committee of 6 senators with at least 2 Democrats?

Tip: Remember, combinations count selections where order doesn't matter. This is why we use (nr)\binom{n}{r} instead of permutations.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Combinatorics
Permutations and Combinations

Formulas

Combination formula: C(n, r) = n! / (r!(n - r)!)

Theorems

-

Suitable Grade Level

Grades 10-12