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Probability - Voter

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Probability - Voter

by Tryingmybest » Wed Mar 25, 2009 5:53 am
There is a 90% chance that a registered voter in Burghtown voted in the last election. If five registered voters are chosen at random, what is the approximate likelihood that exactly four of them voted in the last election?

26.2%
32.8%
43.7%
59.0%
65.6%

OA B
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by Mustang » Wed Mar 25, 2009 8:43 am
prob of person voting : 9/10
prob that person did not vote : 1/10

prob of 4 people voting out of 5 is : (9/10)*(9/10)*(9/10)*(9/10)*(1/10)

= 0.06561

in terms of % it is 6.56%
I am not even close to the answer so let me know where's the mistake:)
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Master | Next Rank: 500 Posts
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by Tryingmybest » Wed Mar 25, 2009 9:21 am
Mustang

You are close indeed :)
there are five different ways to order the one person who didn't vote, so our final result must be 0.06561 × 5 = 0.32805, which is around 32.8%.
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