An urn contains 3 white and 2 blue marbles. The marbles are to be chosen one at a time, until these two marbles are obtained. Denote N as the number of trials required until the 1st blue marble is selected and M as the number of additional trials until the 2nd blue marble is selected.
Find the joint pdf of N and M.

Question

anonymous · Answer

no one know how to solve this??????

anonymous · Answer

what 2 marbles have to be obtained?

anonymous · Answer

@javawarrior i think its the two blue marbles

anonymous · Answer

total marbles = 5

3 white
2 blue 

every marble drawn has a 

60 percent chance that its WHITE
40 percent chance that its BLUE

anonymous · Answer

its been a long time since I did probability but Il give it a crack

if N is the number of trials required to draw the first blue one:

First trial has a 60 percent chance that its white, and 40 percent that its blue

anonymous · Answer

the question is find the joint probability distribution function of N and M, f(N,M) = ???

anonymous · Answer

the question not ask about the percentages.. 
anyone have idea what types of distribution it is?