Math Is Fun Forum

bumbumdee8

Guest

Probability

Help!!!

Suppose that n+1 urns are numbered 0 through n, and the ith urn
contains i red balls and n-i white balls, 0<= i <= n. An urn is
selected at random, and then the balls it contains are removed one by
one, at random, and with replacement.

(a) If the first m balls are all red, what is the probability that the
(m+1)st ball is also red?

(b) Show that, as n approaches infinity, the probability in (a)
approaches (m+1/m+2)

letter (a) should have some sort of summation and letter (b) should use integrals. help?

John E. Franklin

Member

Registered: 2005-08-29

Posts: 3,588

Re: Probability

(a) Since you are doing "replacement" or "putting the ball back in"
each time.  Then the answer is 50%.
The first m balls all red means nothing.

---

igloo myrtilles fourmis

John E. Franklin

Member

Registered: 2005-08-29

Posts: 3,588

Re: Probability

On second thought, the probability probably keeps rising
higher and higher that red will continue, but I'm not
sure how to do it.

---

igloo myrtilles fourmis