Seven people go to a cinema and park their cars outside, which are identical. While returning onlythree of them are able to unlock their cars (assuming that a car can be unlocked only by its ownkey). Find the total number of ways in which this can be done.

A car will hold 2 in the front seat and 1 in the rear seat. If among 6 persons 2 can drive, then the number of ways in which the car can be filled is:

A car will hold 2 in the front seat and 1 in the rear seat. If among 6 persons 2 can drive, then the number of ways in which the car can be filled is:

A flight of stairs has 10 steps.A person can go up the steps one at a time,two at a time,or anycombination of 1s and 2's. Find the total number of ways in which the person can go up the stairs.

A car will hold 2 persons in the front seat and i in the rear seat . If among 6 persons only 2 can drive , the number of ways , in which the car can be filled , is

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 number of ways in which each of the five persons can leave the cabin (i) at any one of the 7 floors (ii) at different floors.

Four persons entered the lift cabin on the ground floor of a six floor office , susppose each of them can leave the cabin independently at any floor beginning with the first . Find the total number of ways in which each of the four persons can leave the cabin at different floors .

Find the number of ways in which five identical balls can be distributed among ten boxes, if not more than one can go into a box.

Five persons entered the lift cabin on the ground floor of an 8 -floor building.If each of them can leave the cabin independently at any floor beginning with the first; find the total number of ways in which each of the five persons can leave the cabin: (i) at any one of the 7 floors and (ii) at different floors.