Math Problem Statement

A firm has 16 senior and 25 junior partners. A committee of three partners is selected at random to represent the firm at a conference. In how many ways can at least one of the junior partners be chosen to be on the committee?

Solution

To solve the problem, we can approach it by first calculating the total number of ways to form a committee of 3 partners from the 41 partners (16 senior + 25 junior), and then subtract the cases where no junior partners are selected.

Step 1: Total number of ways to form a committee

The total number of ways to choose 3 partners from 41 is given by the combination formula:

(413)=41×40×393×2×1=10660\binom{41}{3} = \frac{41 \times 40 \times 39}{3 \times 2 \times 1} = 10660

Step 2: Number of ways where no junior partners are chosen

In this case, all 3 partners must be senior partners. The number of ways to choose 3 partners from the 16 senior partners is:

(163)=16×15×143×2×1=560\binom{16}{3} = \frac{16 \times 15 \times 14}{3 \times 2 \times 1} = 560

Step 3: Number of ways with at least one junior partner

To find the number of ways where at least one junior partner is chosen, we subtract the cases with no junior partners from the total number of ways to form the committee:

Ways with at least one junior partner=(413)(163)=10660560=10100\text{Ways with at least one junior partner} = \binom{41}{3} - \binom{16}{3} = 10660 - 560 = 10100

Thus, the number of ways to form a committee with at least one junior partner is 10,100.

Would you like further details or have any questions?

Related Questions:

  1. How many ways can exactly two junior partners be selected for the committee?
  2. What is the probability that all selected committee members are junior partners?
  3. How many committees can be formed if the firm adds more senior or junior partners?
  4. How would the result change if the committee size was increased to 4 partners?
  5. If one senior partner must be on the committee, how many ways can the committee be formed?

Tip:

Remember that combinations are useful when the order of selection does not matter, while permutations are for when order does matter.

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Math Problem Analysis

Mathematical Concepts

Combinatorics
Combinations
Probability

Formulas

Combination formula: \binom{n}{r} = \frac{n!}{r!(n - r)!}

Theorems

Combination theorem (to calculate the number of ways to select items from a group)

Suitable Grade Level

Grades 10-12