Probability and Stats permutation problem

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SUMMARY

The problem involves calculating the probability that five passengers in an elevator will get off at different floors among seven available floors. The total number of outcomes is determined to be 75, as each passenger can choose any of the seven floors independently. To find the number of favorable outcomes where no two passengers get off at the same floor, the solution requires calculating permutations of the floors chosen by the passengers. Specifically, the number of event outcomes is given by the permutation formula P(7, 5), which equals 7! / (7-5)!. This leads to the final probability calculation of P(E) = P(7, 5) / 75.

PREREQUISITES
  • Understanding of basic probability concepts
  • Familiarity with permutations and combinations
  • Knowledge of factorial notation
  • Ability to apply the probability formula P(E) = number of event outcomes / number of total outcomes
NEXT STEPS
  • Study the concept of permutations in combinatorics
  • Learn how to calculate factorials and their applications in probability
  • Explore examples of probability problems involving multiple independent events
  • Investigate advanced probability topics such as conditional probability and the law of large numbers
USEFUL FOR

Students studying probability and statistics, educators teaching combinatorial concepts, and anyone interested in solving complex probability problems.

billy2908
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Homework Statement



So here's the problem. There is an elevator w/ 5 people equally likely to get off at any of the 7 floor.

What is the probability that no two passengers will get off the same floor.


Homework Equations


The probability of event should be P(E)= number of event outcome/ number of total outcome


The Attempt at a Solution



Total outcome should be 7^5 since
for first floor there can be 1,2,3,4, or 5 people getting off
second floor there can be 1,...,5 people getting off etc.

But I am not sure how to calculate the number of event outcomes.
 
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Total outcome is 7^5 because the first person can choose any of the seven floors to get off on, the second person can choose any of the seven floors to get off on, etc. If they all have to choose different floors then once the first person has chosen, how many choices are left for the second person?
 

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