Fifteen coupons ate numbered 1, z, 3, 15. Seven coupons are selected at random one at a time with replacement. The probability that the largest number appearing on selected coupon is 9 is

Since there are 15 possible cases for selecting a coupon and seven coupons are selected, the total number ofcases of selecting seven coupons is157. It is given that the largest number on the selected coupon is g. Therefore, theselection is to be made from the coupons numbered 1 to 9. This can be made in 97 ways. out of these 97cases, 97 cases do notcontain the number 9. Thus, the favorable number of cases is 97-87. Hence, the required probability is 97−87/157.