Math Problem Statement

As a reward for a record year, a software company is randomly selecting 4 people from its 600 employees for a free trip to Hawaii, but it will not pay for a traveling companion. If John and Jill are married and both are employees, what is the probability that they will both win? (Round your answer to six decimal places.)

Solution

To solve the problem, let's break it down step-by-step.

Step 1: Total Number of Employees

The company has 600 employees in total.

Step 2: Number of Ways to Select 4 Employees

We need to select 4 employees from the 600. The number of ways to choose 4 people out of 600 is given by the combination formula:

(6004)=600!4!(6004)!\binom{600}{4} = \frac{600!}{4!(600 - 4)!}

This represents the total number of possible selections.

Step 3: Number of Ways to Select 4 Employees Including John and Jill

If John and Jill are both selected, we need to choose 2 additional employees from the remaining 598 employees (since John and Jill are already chosen). The number of ways to do this is:

(5982)=598!2!(5982)!\binom{598}{2} = \frac{598!}{2!(598 - 2)!}

Step 4: Probability Calculation

The probability that both John and Jill are selected is the ratio of the favorable outcomes to the total outcomes. Thus, the probability is:

P(both John and Jill win)=(5982)(6004)P(\text{both John and Jill win}) = \frac{\binom{598}{2}}{\binom{600}{4}}

Step 5: Compute the Values

Now let's compute the combinations.

  1. (6004)=600×599×598×5974×3×2×1\binom{600}{4} = \frac{600 \times 599 \times 598 \times 597}{4 \times 3 \times 2 \times 1}
  2. (5982)=598×5972×1\binom{598}{2} = \frac{598 \times 597}{2 \times 1}

We can plug these into the formula to find the exact probability.

Let me calculate these values for you. math

Total number of employees

total_employees = 600

Number of ways to choose 4 employees from 600

total_ways = math.comb(total_employees, 4)

Number of ways to choose 2 employees from the remaining 598 after selecting John and Jill

favorable_ways = math.comb(total_employees - 2, 2)

Probability calculation

probability = favorable_ways / total_ways round(probability, 6)The probability that both John and Jill will win the trip is approximately 0.0000330.000033 (rounded to six decimal places).

Would you like further details or have any questions about this solution?

Here are 5 related questions you may find interesting:

  1. How does the combination formula work when selecting groups from a larger population?
  2. What is the difference between combinations and permutations?
  3. What is the probability of a different couple (other than John and Jill) both winning the trip?
  4. How would the probability change if the company selected 6 employees instead of 4?
  5. How can we calculate the probability of selecting at least one couple for the trip?

Tip: When dealing with probabilities and combinations, remember that combinations count unordered selections, whereas permutations count ordered selections.

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Math Problem Analysis

Mathematical Concepts

Probability
Combinatorics

Formulas

Combination formula: \( \binom{n}{r} = \frac{n!}{r!(n-r)!} \)
Probability formula: \( P = \frac{\text{Favorable Outcomes}}{\text{Total Outcomes}} \)

Theorems

Basic rules of probability

Suitable Grade Level

Grades 9-12