Manipal MET2016MathematicsProbability
Fifteen coupons are numbered 1, 2, ..., 15, respectively. Seven coupons are selected at random one at a time with replacement. The probability that the largest number appearing on a selected coupon is 9 , is
Options
- A( 9 10 )^6
- B( 8 15 )^7
- C( 3 5 )^7
- DNone of these
Correct answer
D. None of these
Step-by-step solution
Every time the selected coupon must be from 1 to 9. The probability of such a selection at any time is 9 15 = 3 5 and this can happen 7 times. i.e. ( 9 15 )^7 . Put of these ( 9 15 )^7, ( 8 15 )^7 cases do not contain the number 9. Thus, the required probability = ( 9 15 )^7- ( 8 15 )^7