Question

4 out of 15 apples are rotten. They are taken out one by one at random and examined. The ones which are examined are not replaced. What is the probability that the 9th one examined is the last rotten one?

Answer 1

The formula for finding out probability =  no. of rotten apples      

                                                                     total no. of apples

so total no. of rotten apples = 4

total no. of apples = 15

so , 4\15