Question

consider there are 6 red balls and 8 blue. suppose we take out one ball at a time, the prob. that 7th ball drawn out is a red ball is?
@cnknd

Answer 1

nope... cuz you could have all first 6 balls be blue, then it's 6/8 chance the 7th is red.
and what if the first 6 balls are 5 blue and 1 red?
what if the first 6 balls are 4 blue and 2 red?
etc..
each case needs to be calculated using conditional probability.
and since all the cases are disjoint, you can just add up the probabilities for your final answer.

i haven't gone through this yet but i suspect the answer might come out to be 6/14 = 3/7