Short Probability (permutation) question

jasper10

1. The problem statement, all variables and given/known data

There is a total of 19 students sitting in a semi-cirlce. How many seating arrangements are possible, if 4 of the 19 students have to sit next to each other?


3. The attempt at a solution

I'm not sure if the calculation is:

15! x 4!

or

19! / 4!

Thanks!

LCKurtz

I would go with the first answer, assuming you can explain it.