[thunderboltsj69]

Q)When 25 ships go into sea, only 5 return, rest drown. In a particular month 15 go on a voyage, what is the probability that 10 return?

[mufasa]

15c10 (1/5)^10 (4/5)^5

[thunderboltsj69]

have i got your interpretation right?

10 ships out of 15 can be chosen in 15C10 ways
and each of those 10 ships has 1/5 probability to return and each of the remaining 5 ships have a probability of not returning of 4/5.
thus (15C10) x { (1/5)^10 } x { (4/5) ^ 5}

thanks so much!

[mufasa]

yup ,thats right.

[TheCat]

guys..please post all your probability question on this thread..

http://www.pagalguy.com/forum/quanti...mbination.html (doubts in permutation & combination)

guys..it becomes extremely difficult for following more number of threads...we use the above thread on discussing p&c and probability questions...

[metallica79]

whts the answer