Probability/statistics question

  • Thread starter meatspin
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  • #1
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Homework Statement


During World War II, a hypothetical city laid out as a 10-by-10 grid of equal size blocks was hit by 200 randomly dropped bombs. Thus, the probability of any particular bomb hitting a specific city block was 1/100 and each block was hit by an average of 2 bombs. Find the probability of a given city block not being hit at all.



Homework Equations





The Attempt at a Solution



1 - (1/100) = P(not being hit).

Just wondering if this was correct and if the fact that an average of 2 bombs and 200 bombs droped would have an impact on the probablity of not being hit.
 

Answers and Replies

  • #2
Each block is hit on average TWO times so it seems reasonable to me that the probability you calculated should represent the probability that the bomb was a failure on BOTH "tries".
 
  • #3
351
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No, the question is asking for the chance that after 200 bombs were dropped, a particular block had not been hit.

You are right that P(not getting hit by a single bomb) = 99/100. So what's P(not getting hit by any of 200 bombs)?
 
  • #4
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is the answer P(not getting hit) = 0.00495
 
  • #5
351
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No. How did you get that?
 

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