Question

How many ways can Elena choose 4 songs from a list of 15 if the order of the songs is important?

Answer 1

Answer:

1365 different ways is your correct answer

Answer 2

Concept:

The concept of permutation is applied here

$n_{p}_{r}=\frac{n!}{(n-r)!}$

Given:

Total number of songs = 15

total number of songs to be chosen= 4

To find:

How many ways Elena can choose 4 songs from a list of 15

Solution:

This question is of permutation and we know the formula for solving permutation questions $n_{p}_{r}=\frac{n!}{(n-r)!}$

Here, n refers to the total number of objects,

r refers to the total number of objects to be selected

and p refers to permutation.

The value of n in this question is 15

r=4

Now, if we put these values in the formula of permutation we get,

$n_{p} _{r} =\frac{n!}{(n-r)!}\\\frac{15!}{(15-4)!} \\\frac{15!}{(11)!} \\\frac{15*14*13*12*11!}{11!}$

Now we know that 11! will be canceled from 11!

so we get

$15*14*13*12\\32760$

∴Elena can choose 4 songs from a list of 15 in 32760 ways.

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