Correct Answer - C
Besides ground floor, there are 7 floors. Since a person can leave the cabin at any of the seven floors, therefore the total number of ways in which each of the five persons can leave the cabin at any of the 7 floors =75
.
∴
Total number of ways =75
.
Five persons can leave the cabin at five different floors in .7C5×5!
ways. Therefore,
∴
Favourable number of ways =.7C5×5!
Hence, required probability =
.7C5×5!
75