Question

In how many orders can six people line up from left to right for a group photo?

Answer 1

We have to arrange 6 people in line

. Now, the number of ways to arrange n items = n!.

Hence, the answer is 6!=

=6×5×4×3×2×1= 720 orders

Answer 2

720 possible orders

Explanation:

To order 6 people in a line, let's imagine them as 6 possible spaces:

( )( )( )( )( )( )

Going from left to right, let's start with space 1.

There are 6 possibilities for space 1 as any of the 6 people could occupy that space in the line.

(6)( )( )( )( )( )

Next, since one person will have already occupied space 1, there are only 5 people left who can occupy space 2, so there are 5 possibilities for space 2:

(6)(5)( )( )( )( )

Continuing in this fashion, there are now only 4 people left so 4 possibilities for space 3 and etc.

(6)(5)(4)(3)(2)(1)

This means we have 6,5,4,3,2 and 1 possibilities for each space respectively.

Multiply them together and we have:

6x5x4x3x2x1 = 720 possible orders.

Hope this helped!