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45 votes
(a) A company has 39 salespeople. A board member at the company asks for a list of the top 5

salespeople, ranked in order of effectiveness. How many such rankings are possible?

User Sachin Sharma
by
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2 Answers

16 votes
16 votes

Final answer:

The number of different rankings of the top 5 salespeople from a group of 39 is calculated using permutations. P(39, 5) = 39! / 34! simplifies to 39 × 38 × 37 × 36 × 35, which equals 69,090,840 possible rankings.

Step-by-step explanation:

To determine how many different rankings of the top 5 salespeople are possible from a group of 39, we can use the concept of permutations, which considers the order of selection. When we select 5 out of 39 without replacement and where the order matters, we calculate the number of permutations as follows:

P(n, k) = n! / (n - k)! where n is the total number of items to choose from, and k is the number of items to choose.

In this case, n = 39 salespeople and k = 5 top salespeople to rank. So the calculation would be:

P(39, 5) = 39! / (39 - 5)!

This simplifies to:

P(39, 5) = 39! / 34!

The factorial symbol (!) represents the product of all positive integers up to that number. Therefore:

39! = 39 × 38 × 37 × 36 × 35 × 34!

To find the number of possible rankings, we cancel out the 34! from both the numerator and denominator and multiply the remaining numbers:

39 × 38 × 37 × 36 × 35

By completing the multiplication, we find that there are a total of 69,090,840 possible rankings of the top 5 salespeople from 39.

User Vishr
by
2.8k points
12 votes
12 votes

Answer:

69090840 possible rankings

Step-by-step explanation:

The number of possible ranking ordered in terms of effectiveness can be obtained using permutation

Number of salesperson = 39

Number of rank = 5

nPr = n! ÷ (n - r)!

nPr = 39P5

39P5 = 39! ÷ (39 - 5)!

39P5 = 39! ÷ 34!

39P5 = 39 * 38 * 37 * 36 * 35 = 69090840

User Roylaurie
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2.9k points