Question

There are 10 chairs in a row.
a In how many ways can three people be seated?
b In how many of these will the two end chairs be occupied?
c In how many of these will the two end chairs be empty?

Answer 1

stuck on b!

Answer 2

1. we have 10 chairs and 3 people, so combination would be 10C3

Answer 3

1 is 10P3 = 720 not combination

Answer 4

i guess, combination.. because no specific sequence is given...

Answer 5

2. assume last two seats are occupied by two people from three..

SO i guess, 3C2... and remaining chairs will be filled by that one person..

so = 3C2 * 8C1.. ??

Answer 6

its 3P2 x 8P1 = 48 close

Answer 7

I am not getting how it is Permutation ?? it can be any order...

Answer 8

umm cause u can have the 3 person in different positions i think

Answer 9

yes, different positions and no specific positions..
So it should be combination... well, if you ask me..

Answer 10

3. two end chairs empty , means they can occupy all between chairs.. so 8C3..

Answer 11

let 3 person = A,B,C
u can have _____A__BC, _______B__CA ??

Answer 12

8P3 again

Answer 13

so that is combination.. right ??

If the order doesn't matter, it is a Combination.

Answer 14

:D

Answer 15

@ganeshie8 : dude, help identify ... permutation or combination ??

Answer 16

i mean _____A__BC, _______B__CA count as 2 ways.. even if occupying same positions

Answer 17

A B C, C B A, B A C, B C A.. so on

Answer 18

its permutation cause u can swap the 3 person around in the same positions

Answer 19

It is a permutation because there is exactly three people you have yo seat. If it was a combination you would seat 10 people. In this case they want you to find the order in which 3 people can be sat hence it is a permutation.