Five persons entered the lift cabin on the ground floor of an 8 - floor house. Suppose each of them can leave the cabin independently at any floor beginning with the first. Find the total no. of ways in which all the five persons can leave the cabin at different floors.

Dear Sanchit Gupta

1st  person can leave at any of seven floors in 7 ways

2nd  person can leave at any of seven floors in 6 ways

3rd person can leave at any of seven floors in 5 ways

4th person can leave at any of seven floors in 4 ways

5th person can leave at any of seven floors in 3 ways

total ways =7*6*5*4*3 =2520