SOLUTION: A box contains n balls marked from 1 to n.Two balls drawn in succession with replacement. Find the probability that number on the balls are consecutive integers(ignore the order of
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Question 1133941: A box contains n balls marked from 1 to n.Two balls drawn in succession with replacement. Find the probability that number on the balls are consecutive integers(ignore the order of balls)?
I find it 2*(n-1)/n^2.
Is that correct? Found 2 solutions by Glaviolette, ikleyn:Answer by Glaviolette(140) (Show Source):
You can put this solution on YOUR website! We really just need to think about the 2nd ball being either one less than or one more than the first ball. That means there are 2 successful balls out of all of the balls. So, I believe the answer is 2/n.
The full space of all possible outcomes is (n x n) - matrix with elements (events) that are equally likely.
Of these outcomes, the favorable are those that are one diagonal above or one diagonal below the major diagonal.
So, the number of favorable outcomes is 2*(n-1) against the total number of outcomes of .
Therefore, the answer is , the same as in your post.
Thus your answer is correct.
