about to only mathematics

Options

A. `((9)/(196))^(6)`
B. `((8)/(15))^(7)`
C. `((3)/(7))^(7)`
D. None of these

Answer

D

Explanation

Since, there are 15 possible cases for selecting a coupor and seven coupons are selected, the total number o cases of selecting seven coupons =`15^7`
It is given that the maximum ·number on the selecte coupon is 9, therefore the selection is to be made from the coupons numbered 1 to 9. This can be made in r ways. Out of these `9^7` cases `8^7` does not contain the number 9.
Thus, the favourable number of cases `=9^7-8^7`
`therefore` Required probability `=(9^7-8^7)/(15^7)`