- #1
SW VandeCarr
- 2,199
- 81
What is the probability of getting a duplicate of a digit in a randomly generated sequence of four digits?
I would approach this intuitively as follows.
(1.0)(0.1)(0.9)(0.9)=0.081
" (0.1)(0.1)(0.9)=0.009
" (0.1)(0.1)(0.1)=0.001
Sum =0.091
There must be a more efficient and elegant way of doing this but I've not been able to find one. Also, is there a more general formula for a set of n distinct objects each with a probability 1/n of being selected?
I would approach this intuitively as follows.
(1.0)(0.1)(0.9)(0.9)=0.081
" (0.1)(0.1)(0.9)=0.009
" (0.1)(0.1)(0.1)=0.001
Sum =0.091
There must be a more efficient and elegant way of doing this but I've not been able to find one. Also, is there a more general formula for a set of n distinct objects each with a probability 1/n of being selected?
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