Probability - Franks

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Suppose that a torpedo has a probability of 1/3 of sinking a ship,1/3 of damaging it and 1/3 of missing it altogether,and also two damaging shots will sink the ship.What is the probability that 4 torpedoes will sink the ship ?
(3 marks)

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can someone please solve this question...! I didnt get it either..!

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is it 2/81 Question

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in which paper of franks is this question is
the prob of damaging =1/3
prob of sinking=1/3....................1
2 damaging shots sink the ship so
prob of sinking a ship by two damaging shots = 1/3 * 1/3 =1/9...................2
adding 1 n 2
total prob of damaging in 2 shots= 1/3 + 1/9 =4/9
therefore prob of damaging in 4 shots = 4/9 + 4/9 = 8/9

im not sure Probability - Franks Icon_question

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r u sure

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im not sure of it!! if some one tells me in which paper of franks book is this Q or what is the answer given to the problem.......... i may verify

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@RC WHAT SPECIMEN PAPER IS THIS QUESTION FROM ? Probability - Franks Icon_king

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my answer is ...76/81.....n i m quite sure... Smile

.......i hav done this using Tree method....i know that way its lengthy but u get answer......and also it shd be very high as their are 4 shots...!

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Hey Whats the answer for this question??
cn u plz post!!!

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plzzz verify my ans..........aren't ans. given in Frank papers..??? Question

Subject: Re: Probability - Franks Sat Mar 20, 2010 11:45 pm

UR ANS IS RITE ....ITS 76/81

Subject: Re: Probability - Franks Sat Mar 20, 2010 11:46 pm

I 2 SOLVD IT N GOT D SAME ANS...

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ya me 2...bt i wil nt b doin it tho,,..!!

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yes ur ans is right..76/81

i have an old edition in which it is in Model Unsolved Paper 9

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shreyk can u post ur soln.

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i get the answer as 50/81..!! suppose we take the probability of not sinking the ship and we subtract it from 1, we get the probability of sinking the ship..

the conditions when she ship does not sink is when
1)all four misses[very low prob 1/81]
2)one damaging shot and three misses [1/3 + 1/27]

the doubt is for case 2 do we have to do the permutation combiination too..??
if so..how..?

i did not do it and by add prob 1 and prob 2 i get 50/81

anything wrong in my assunption..?

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i suggest u to try by Tree method....this method is too confusing for me...and yes for damage and misses...u have to use P n C....thatz y Tree method is easier...

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scratch my last post...!!! I got the answer... 76/81 it is..

those who did it..confirm if this is how u got it..!

all four misses 1/81

one hit and three misses 4/81

total prob 5/81

therefore prob of sinking is 1- 5/81 = 76/81

y0..!! lol!

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i got it too...

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All the very best guyz..! Do well..! God bless Gerry Arathoon if the papr is easy...!!! lol!

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May Satan bless him if he givs a BIG "BAMBOO" to us..~~!!! : Twisted Evil

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Why bother satan..? i will personally visit him..!! lol!

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wel said ma'i'te..!! lol!