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Probability Problem


 
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richs_ca
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PostPosted: Fri May 02, 2008 12:17 pm    Post subject: Probability Problem Reply with quote
In a survey of students, each student selected from a list of 12 songs the 2 that the student liked best. If each song was selected 4 times, how many students were surveyed?

a) 96
b) 48
c) 32
d) 24
e) 18

I don't even know where to start!

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simplyjat
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PostPosted: Fri May 02, 2008 12:20 pm    Post subject: Reply with quote
Total number of songs = 12
Each song was selected 4 times, so total selections = 12*4 = 48
One student can select 2 songs, so number of students = 48/2 = 24
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chipjet
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PostPosted: Fri Jun 13, 2008 1:49 pm    Post subject: Reply with quote
The best approach to this is to think what exactly is happening. If each student (x) gets to pick 2 songs each, that product can be divided by 12 to get to 4.

In a formula:
(2x)/12 = 4

Solve for x = 24
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