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For a segment of a radio show a disc jockey complain 9 records if there are 14 records to select from and how many ways can the program for the segment be arranged

User Dan Klos
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2 Answers

3 votes

To determine the number of ways the program for the segment can be arranged, we must calculate the number of permutations of 9 records from a set of 14.

A permutation is an arrangement of items where order matters. When selecting r items from a set of n without replacement, the number of permutations is given by the formula:

\[ P(n, r) = n! / (n - r)! \]

where \( n! \) (n factorial) represents the product of all positive integers from 1 to n, and \( (n - r)! \) is the factorial of the difference between n and r.

Now let's solve the problem step by step.

Step 1: Identify n and r.
- n (total number of different records to select from) = 14
- r (number of records to arrange) = 9

Step 2: Apply the permutation formula.

\[ P(14, 9) = \frac{14!}{(14 - 9)!} = \frac{14!}{5!} \]

Step 3: Calculate factorials and simplify.

\( 14! \) (14 factorial) means the product of all positive integers from 1 to 14:

\[ 14! = 14 \times 13 \times 12 \times 11 \times 10 \times 9 \times 8 \times 7 \times 6 \times 5 \times 4 \times 3 \times 2 \times 1 \]

\( 5! \) (5 factorial) is the product of all positive integers from 1 to 5:

\[ 5! = 5 \times 4 \times 3 \times 2 \times 1 \]

Step 4: Divide 14! by 5! to find the number of permutations.

Since \( 5! \) is a factor in both the numerator and the denominator, we can simplify the calculation by canceling out the common factors.

\[ P(14, 9) = \frac{14 \times 13 \times 12 \times 11 \times 10 \times 9 \times 8 \times 7 \times 6}{5 \times 4 \times 3 \times 2 \times 1} \]

The \( 5 \times 4 \times 3 \times 2 \times 1 \) in the denominator will cancel out the \( 5 \times 4 \times 3 \times 2 \times 1 \) in the numerator, so we're left with:

\[ P(14, 9) = 14 \times 13 \times 12 \times 11 \times 10 \times 9 \times 8 \times 7 \times 6 \]

Step 5: Calculate the product of the remaining factors to get the final answer.

\[ P(14, 9) = 14 \times 13 \times 12 \times 11 \times 10 \times 9 \times 8 \times 7 \times 6 = 1,037,836,800 \]

So there are 1,037,836,800 different ways the disc jockey can arrange the 9 records for the segment of the radio show.

User Lica
by
6.4k points
1 vote

Answer:

Number of ways the program for the segment be arranged = 726,485,760 ways

Explanation:

Since the question asks how many ways the program be arranged, to me it implies that order matters. Then the number of ways is;

P(14,9) = 14!/(14 - 9)!

= 14!/5!

= (14 × 13 × 12 × 11 × 10 × 9 × 8 × 7 × 6 × 5!)/5!

5! will cancel out to give;

14 × 13 × 12 × 11 × 10 × 9 × 8 × 7 × 6 = 726485760 ways

User Francoisxavier
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5.7k points