Question

If 15 coupons are numbered 1, 2, 3, ..., 15, respectively. 7 coupons are selected at random one at a time with replacement. The probability that the largest number appearing on a selected coupon is almost 9, is ______.

Options

• `(1/15)^7`

• `(3/5)^7`

• `(8/15)^7`

• None of these

Answer 1

If 15 coupons are numbered 1, 2, 3, ..., 15, respectively. 7 coupons are selected at random one at a time with replacement. The probability that the largest number appearing on a selected coupon is almost 9, is `underlinebb((3/5)^7)`.

Explanation:

Given, total coupons = 15

1 ≤ selected coupon number ≤ 9

i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9

∴ Probability of one selected coupon = `9/15 = 3/5`

Hence, the required probability

= `(3/5) xx (3/5) xx (3/5) xx (3/5) xx (3/5) xx (3/5) xx (3/5)`

= `(3/5)^7`