Question

A certain number of friends are waiting in line to board a new rollercoaster they can board the ride in 5040 different ways. How many friends are in line?

Answer 1

`1!=1=1\\2!=2*1=2\\3!=3*2*1=6\\4!=4*3*2*1=24\\5!=5*4*3*2*1=120\\6!=6*5*4*3*2*1=720\\7!=7*6*5*4*3*2*1=5040`

7 friends.