

Author  Message 

RC Active member
 Subject: Probability  Franks Sat Mar 20, 2010 2:34 pm  
 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) 

 
G7 Active member
 Subject: Re: Probability  Franks Sat Mar 20, 2010 2:55 pm  
 can someone please solve this question...! I didnt get it either..! 

 
anjanavr47 Active member
 Subject: Re: Probability  Franks Sat Mar 20, 2010 5:22 pm  
 is it 2/81 

 
neeha Active member
 Subject: Re: Probability  Franks Sat Mar 20, 2010 5:33 pm  
 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
Last edited by neeha on Sat Mar 20, 2010 5:49 pm; edited 1 time in total 

 
anjanavr47 Active member
 Subject: Re: Probability  Franks Sat Mar 20, 2010 5:45 pm  
 r u sure 

 
neeha Active member
 Subject: Re: Probability  Franks Sat Mar 20, 2010 5:48 pm  
 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 

 
NITIN BHUWANIA Active member
 Subject: Re: Probability  Franks Sat Mar 20, 2010 8:10 pm  
 @RC WHAT SPECIMEN PAPER IS THIS QUESTION FROM ? 

 
Uber Active member
 Subject: Re: Probability  Franks Sat Mar 20, 2010 8:18 pm  
 my answer is ...76/81.....n i m quite sure... .......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...! 

 
kool Active member
 Subject: Re: Probability  Franks Sat Mar 20, 2010 8:18 pm  
 Hey Whats the answer for this question?? cn u plz post!!! 

 
Uber Active member
 Subject: Re: Probability  Franks Sat Mar 20, 2010 10:31 pm  
 plzzz verify my ans..........aren't ans. given in Frank papers..??? 

 
shreyk
 Subject: Re: Probability  Franks Sat Mar 20, 2010 11:45 pm  
 UR ANS IS RITE ....ITS 76/81 

 
shreyk
 Subject: Re: Probability  Franks Sat Mar 20, 2010 11:46 pm  
 I 2 SOLVD IT N GOT D SAME ANS... 

 
Soumava Active member
 Subject: Re: Probability  Franks Sat Mar 20, 2010 11:52 pm  
 ya me 2...bt i wil nt b doin it tho,,..!! 

 
RC Active member
 Subject: Re: Probability  Franks Sun Mar 21, 2010 9:21 am  
 yes ur ans is right..76/81
i have an old edition in which it is in Model Unsolved Paper 9 

 
RC Active member
 Subject: Re: Probability  Franks Sun Mar 21, 2010 9:33 am  
 shreyk can u post ur soln. 

 
G7 Active member
 Subject: Re: Probability  Franks Sun Mar 21, 2010 1:14 pm  
 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..? 

 
Uber Active member
 Subject: Re: Probability  Franks Sun Mar 21, 2010 2:23 pm  
 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... 

 
G7 Active member
 Subject: Re: Probability  Franks Sun Mar 21, 2010 2:41 pm  
 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..!! 

 
anjanavr47 Active member
 Subject: Re: Probability  Franks Sun Mar 21, 2010 11:13 pm  
 i got it too... 

 
G7 Active member
 Subject: Re: Probability  Franks Mon Mar 22, 2010 12:01 am  
 All the very best guyz..! Do well..! God bless Gerry Arathoon if the papr is easy...!!! 

 
Soumava Active member
 Subject: Re: Probability  Franks Mon Mar 22, 2010 12:03 am  
 May Satan bless him if he givs a BIG "BAMBOO" to us..~~!!! : 

 
G7 Active member
 Subject: Re: Probability  Franks Mon Mar 22, 2010 12:12 am  
 Why bother satan..? i will personally visit him..!! 

 
Soumava Active member
 Subject: Re: Probability  Franks Mon Mar 22, 2010 12:46 am  
 wel said ma'i'te..!! 

 
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 Subject: Re: Probability  Franks  



 
