Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:
Can't prove me wrong there
but I'll also go with C
A&B never together = Total - A&B always together
Total =5! =120
A&B always together = 4!2! =48
(for A&B always together, treat A&B as one unit so you have total 4 units and hence the 4!, but A&B can switch places amongst themselves and so the 2!)
Total number of ways to seat 5 people in a row = 5! = 120
number of ways A and B will seat with each other = 4!2! = 48
So number of ways to seat 5 people when A and B don't sit next to each other = 120-48 =72