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Dan Jones, was a classmate of Shawn Fanning, at Northeastern, and made early use of Fanning's Napster to download 300 MP3s.

 

The collection he dowloaded contained:

Hip-hop 47

Heavy Metal 59

Rock 80

Punk 54

Reggae 46

Celtic Folk 14

 

Now known as "DJ Dan", he hosts a radio show on WPRS, a pirate radio station that broadcasts from a dinghy off the coast of Nantucket. Six songs with a lot of chat fills his half hour of daily air time. If two programs are considered the same only if he plays the same songs in the same order, how many different programs can DJ Dan offer if

 

he plays 1 Hip-hop and 5 Celtic Folk MP3s, with no repetition?

 Feb 25, 2015

Best Answer 

 #1
avatar+128578 
+5

We can first count sets and then arrangements of those sets

We want to choose 1 of the 47 hip-hop MP3s and any 5 of the 14 Celtic Folk MP3s

The total number of sets of songs is given by C(47,1)* C(14,5) = 94094

But......each set of songs can be arranged in 6! = 720 ways

So   94094 x 720 = 67,747,680 different programs

 

 Feb 25, 2015
 #1
avatar+128578 
+5
Best Answer

We can first count sets and then arrangements of those sets

We want to choose 1 of the 47 hip-hop MP3s and any 5 of the 14 Celtic Folk MP3s

The total number of sets of songs is given by C(47,1)* C(14,5) = 94094

But......each set of songs can be arranged in 6! = 720 ways

So   94094 x 720 = 67,747,680 different programs

 

CPhill Feb 25, 2015
 #2
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0

I thought that was the answer too, but it turned out that wasn't correct.

 Feb 25, 2015

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