1. ## probability(1)

(1) fifteen coupons are numbered $1,2,3,.......,15$.Seven Coupons are selected at random with replacement. Then find the probability no. appearing on a selected coupons is $9$

2. Originally Posted by jacks
(1) fifteen coupons are numbered $1,2,3,.......,15$.Seven Coupons are selected at random with replacement. Then find the probability no. appearing on a selected coupons is $9$
Then find the probability no. appearing on a selected coupons is 9
How many selected coupons?

What you have here is a binomial distribution with n = 7 and p = 1/15.

If you need more help, please clarify the question, show what you've tried and say where you are stuck.

3. actually I have not getting any idea in that question.

Thanks.