probablity

If a rod is marked random at n points and divided at these points,the chance that none of the parts shall be greater than 1/n th of the rod is 1/nn

14 Answers

62
Lokesh Verma ·

this one is bugging me for the last 2 days.. i cant think of a solution at all :(

Am still trying! :)

24
eureka123 ·

okkkkk.......soln hasnt struck me tooo......Me trying for more than 5 dayz..

24
eureka123 ·

Sir have u solved it?

9
Celestine preetham ·

note ; made some mistakes in exp that ive edited in end

edit : abv corresponds to div rod into n+1 regions

i wrongly wrote as n region

also the graphs r rong

wen , n =1 ,its line x+y = 1 in ist coordinate (so region prop to l)
wen, n =2 its plane x+y+z =1 in ist coordinate ( so region prop to l2)
similarly for any n , its region prop to l^n

9
Celestine preetham ·

contd ..........

so P = cases of div rod into n+1 pieces for rod of lenght l/n / that of l

= (l/n)^n/ l^n = 1/n^n

9
Celestine preetham ·

62
Lokesh Verma ·

i dont agreee to your solution.. you have made a small error

|x|+|y|+|z| = 1 is the graph...

these are all planes... 8 of them..

so they will form a diamond like structure..

a cube with diagonal equal to? (for u to answer) :)

was out of my mind when i was posting this one :D

62
Lokesh Verma ·

or is it that i did not udnerstand your solution?

9
Celestine preetham ·

no sir i don agree wit u

X + Y + Z = 1 will be graph with x , y , z >0

62
Lokesh Verma ·

oops ok.. yes... i am completely out of mind :D :P

9
Celestine preetham ·

nishant now sol seems to be right

even i was out of mind for drawin feasible region as sqr and volumes

62
Lokesh Verma ·

celestine i forgot to post this one last nite.. i had the solution in mind..

see for a 3d case it will be a cube of side 1/3 from the origin in the 1st quadrant

and the overall part will be by the plane x+y+z=1

so the probability will be given by the volume ratio...

I dnot knwo if this is what you mean :)

9
Celestine preetham ·

no its not volume ratio for n=2

its area ratio

see my edit abv

9
Celestine preetham ·

also ignore those pics that i posted they r totally rong

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