Problem Solving (PS) | Re: How many different arrangements to seat four spectators in four of sev

Since there are 7 empty seats and we need to seat four spectators in four of
the empty stadium seats, there are 7 ways of seating the first spectator.
There are 6,5, and 4 ways of seating the other 3 spectators.

Therefore, there are 7*6*5*4 = 42*20 =840 ways(Option E) of seating the 4 spectators
...

---