Problem

Use permutations to solve.
Tim is a huge fan of country music. If Tim has time to listen to only 7 of the 11 songs on an album, how many ways can he listen to the 7 songs?

Substitute values into the formula for ${ }_{n} P_{r}$.
\[
{ }_{n} P_{r}=\frac{\square !}{(\square-\square) !}
\]
(Type an integer or a decimal.)

Answer

Expert–verified
Hide Steps
Answer

So, the number of ways Tim can listen to the 7 songs is \(\boxed{1663200}\).

Steps

Step 1 :Given that Tim has time to listen to only 7 of the 11 songs on an album, we are asked to find out how many ways he can listen to the 7 songs.

Step 2 :We can solve this problem using permutations. The formula for permutations is given by \( { }_{n} P_{r}=\frac{n!}{(n-r)!} \), where \( n \) is the total number of items, and \( r \) is the number of items to choose.

Step 3 :Substitute \( n = 11 \) and \( r = 7 \) into the formula, we get \( { }_{11} P_{7}=\frac{11!}{(11-7)!} \).

Step 4 :Calculate the factorial of 11 and 4, we get \( { }_{11} P_{7}=\frac{39916800}{24} \).

Step 5 :Simplify the above expression, we get \( { }_{11} P_{7}=1663200 \).

Step 6 :So, the number of ways Tim can listen to the 7 songs is \(\boxed{1663200}\).

link_gpt