Question 3.
Number of people boarding the plane = 12
Number of people with first class tickets = 4
Let's find the number of ways the 12 people can board the plane if those with first class tickets board before those with economy class.
Number of people with economy class = 12 - 4 = 8
If the 4 people with first class board first before the 8 with economy class tickets, we have:
Number of ways = 4! 8!
Number of ways = 4 x 3 x 2 x 1 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 967680
Therefore, there are 967680 ways to board the plane.
ANSWER:
967680