Question

DJ Mykel is making a playlist for a radio show; he is trying to decide what 14 songs to play and in what order they should be played. Step 1 of 2 : If he has his choices narrowed down to 7 hip-hop, 5 jazz, 7 pop, and 8 blues songs, and he wants to play no more than 3 hip-hop songs, how many different playlists are possible

Answer 1

5878600 different playlists.

Explanation:

Since we require 14 songs for the playlist and there are 7 hip-hop, 5 jazz, 7 pop, and 8 blues songs, and DJ Mykel wants to play no more than 3 hip-hop songs, the number of ways in which he can combine the 7 hip-hop songs to play no more than 3 is ⁷C₃ = 7!/4!3!.

Now, since we have 3 songs already selected, we are left with 14 - 3 = 11 songs to select.

Since we have selected the 3 hip-hop songs, we are left with 5 jazz, 7 pop, and 8 blues songs which sum to a total of 20 songs.

So, we have 20 songs to select in 11 ways which is ²⁰C₁₁ = 20!/(20 - 11)!11! = 20!/9!11!

So, the number of different playlists that can be formed is thus

⁷C₃ × ²⁰C₁₁ = 7!/4!3!.× 20!/9!11!

= 35 × 167960

= 5878600 different playlists.