Math Problem Statement

7 people visited a marriage function in 3 different vehicles, each accommodating a maximum of 5 persons. In how many ways can they visit, such that they use all the 3 vehicles?

Solution

The problem in the image states:

"7 people visited a marriage function in 3 different vehicles, each accommodating a maximum of 5 persons. In how many ways can they visit, such that they use all the 3 vehicles?"

Solution:

  1. Understanding the distribution problem:

    • We need to distribute 7 people into 3 vehicles.
    • Each vehicle must carry at least 1 person, and no vehicle can carry more than 5 people.
  2. Step 1: Breaking down the number of people into vehicles. Since there are 7 people and all vehicles must be used, we need to find how to split 7 people into groups where each group has at least 1 person.

    This is a classic combinatorics problem of distributing people into groups with restrictions. The combination of groups is solved using the stars and bars approach and factorial calculation for permutations.

  3. Step 2: Distribution options The only valid group distributions are:

    • (3, 2, 2): One vehicle has 3 people, and the other two vehicles have 2 people each.
  4. Step 3: Calculating the number of ways to assign people:

    • First, choose 3 people to go in the vehicle carrying 3 people. This can be done in (73)=7!3!(73)!=35\binom{7}{3} = \frac{7!}{3!(7-3)!} = 35 ways.
    • After assigning 3 people, we have 4 people left. We need to assign 2 people to one vehicle and 2 to the other.
    • The number of ways to split these 4 people into two groups of 2 is (42)2!\frac{\binom{4}{2}}{2!}. We divide by 2!2! because the two groups of 2 are indistinguishable. This gives 62=3\frac{6}{2} = 3 ways.
  5. Step 4: Total number of ways: The total number of ways to distribute the 7 people into the 3 vehicles is 35×3=10535 \times 3 = 105.

However, upon review, we need to adjust for ordering of vehicles and revisit combinatorics for constraints,

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Math Problem Analysis

Mathematical Concepts

Combinatorics
Permutations
Combinations
Stars and Bars

Formulas

Combination formula: \( \binom{n}{r} = \frac{n!}{r!(n-r)!} \)
Permutation formula for groupings: \( P(n, r) = \frac{n!}{(n-r)!} \)
Stars and bars method for distributing items into groups

Theorems

Combinatorics theorem for distributing items into groups

Suitable Grade Level

Grades 9-12