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April 4th, 2011, 11:26 AM   #1
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need a help with 2 probabilities

Code:
1.The pedestrian can cross a street within 3 seconds.The pedestrian start walk then he sees that in 3 seconds period no car cross a street.Probability that within 1 second a car will cross a street is 0.54.what probability that the pedestrian will wait 2 seconds until he gets a chance to cross a street
Code:
2.Hunter A has probability to shoot successfully a target 0.56.Hunter B has probability to shoot successfully  a target 0.65.Independently they are shooting into target until the first successful hit.What probability that for the first hunter will need more ammunition than for the second
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April 4th, 2011, 12:22 PM   #2
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Re: need a help with 2 probabilities

Hello, safyras!

The second problem is not stated clearly.
Some clarification is needed.


Quote:
2. Hunter A can hit a target with probability 0.56.
Hunter B can hit the target with probability 0.65.
Independently they shoot at a target until the first hit.
What probability that for the first hunter will need more ammunition than the second?

We must assume a number of rules . . . which is always dangerous.

Do the two hunters fire at the target at the same time, firing the same number of times?
[color=beige]. . [/color](If they do not fire together, do they take turns? . . . A-B-A-B- ... )

The problem says "... until the first hit".
[color=beige]. . [/color]This means that they stop, right?
Then why would a hunter need "more ammunition"?

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April 4th, 2011, 12:53 PM   #3
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Re: need a help with 2 probabilities

thanks for answer, soroban.


Quote:
The problem says "... until the first hit".
. . This means that they stop, right?
Then why would a hunter need "more ammunition"?
Yes , they stop .
Quote:
Then why would a hunter need "more ammunition"?
Two hunters shooting at the same time.What probability that hunter A will use more bullets than hunter B to hit a target.
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April 4th, 2011, 01:47 PM   #4
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Re: need a help with 2 probabilities

Hello again, safyras!

Quote:
Two hunters shooting at the same time.
What probability that hunter A will use more bullets than hunter B to hit a target?

That still doesn't clear up the mystery.

[color=beige]. . [/color]

and they stop . . . So hunter A will not get a chance to use "more bullets".


Could the question be: "What is the probability that Hunter B gets the first hit?"

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April 4th, 2011, 02:06 PM   #5
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Re: need a help with 2 probabilities

Quote:
Could the question be: "What is the probability that Hunter B gets the first hit?"
okey.How to solve it?
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April 5th, 2011, 03:47 AM   #6
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Re: need a help with 2 probabilities

Code:
    1.The pedestrian can cross a street within 3 seconds.The pedestrian start walk then he sees that in 3 seconds period no car cross a street.Probability that within 1 second a car will cross a street is 0.54.what probability that the pedestrian will wait 2 seconds until he gets a chance to cross a street
could i solve the first in this way:

where
P=0.54
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April 5th, 2011, 04:21 AM   #7
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Re: need a help with 2 probabilities

Quote:
Could the question be: "What is the probability that Hunter B gets the first hit?"
so could i solve it like that
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April 5th, 2011, 08:25 AM   #8
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Re: need a help with 2 probabilities

Hello, safyras!

Thanks for the clarification . . . I think I have the answer.

I had to use baby-talk to get the picture.



[color=beige]. . [/color]


[color=beige]. . [/color]




[color=beige]. . [/color]




[color=beige]. . [/color]




[color=beige]. . [/color]




[color=beige]. . [/color]






[color=beige]. . . . . . . . . [/color]




[color=beige]. . [/color]





~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~




[color=beige]. . [/color]




[color=beige]. . [/color]



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April 5th, 2011, 12:48 PM   #9
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Re: need a help with 2 probabilities

Thanks for solution,soroban.How to solve the first problem?
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