Question

At the airport, ten people are waiting on standby. Two seats become available, one first class and one coach. How many ways are there to fill the two seats?

10
20
45
90

Answer 1

To determine how many ways there are to fill the two available seats (one first class and one coach) from the ten people waiting on standby, we can think of the process in two steps:

1. **Select a person for the first class seat.** There are 10 people available, so we have 10 choices for this seat.

2. **Select a person for the coach seat.** After selecting someone for the first class seat, there are now 9 people remaining who can be chosen for the coach seat.

Therefore, the total number of ways to fill the two seats is calculated by multiplying the number of choices for each seat:

\[
10 \text{ (choices for first class)} \times 9 \text{ (choices for coach)} = 90
\]

Thus, the total number of ways to fill the two seats is \( \boxed{90} \).