Question

Four friends are going to sit in a row on a bench to have their picture taken. In how many different orders can the four friends sit?

Answer 1

ooh! funzies!! So there are two ways to do this problem, logic or graphical, you pick

Answer 2

Logic. But if that doesn't work for me then I will chose graphical.

Answer 3

k so let's name the friends 1,2,3,4 and the positions a,b,c,d respectively

Answer 4

how many options do you have at position 1 when 2,3,4 are empty?

Answer 5

4?

Answer 6

oops, position a, b,c,d are empty

Answer 7

and yes 4 that is correct. now how many options do you have for position b once a is filled?

Answer 8

3? Since you can fill up the positions of b,c, and d.

Answer 9

well 3 since you have 3 people left, but 3 is correct, now how about c?

Answer 10

2. Since c and d is empty.

Answer 11

2 because you have people 3 and 4 left

Answer 12

now d?

Answer 13

1

Answer 14

k so we went from 4 to 3 to 2 to 1. if we multiply these that will give us the max permutation. this can also be denoted 4!

Answer 15

!=factorial

Answer 16

What does permutation mean?

Answer 17

permutation is the number of ways a group can be mixed up with the order mattering. combination means order doesn't matter (i might have those backwards)

Answer 18

yep just checked, is this for an abstract algebra class per chance?

Answer 19

No I am just learning. :)

Answer 20

ahh ok well i suggest MIT opencourseware for a video class it's pretty sweet