Aliane created a table showing the flight information for four cities.

\begin{tabular}{|l|l|l|}
\hline Departing From & Arriving At & Flight Time \\
\hline City A & City B & 4.2 hours \\
\hline City A & City C & 3.9 hours \\
\hline City B & City A & 5.1 hours \\
\hline City B & City D & 9.5 hours \\
\hline City C & City B & 1.7 hours \\
\hline City C & City D & 2.2 hours \\
\hline City D & City A & 10.5 hours \\
\hline City D & City B & 8.6 hours \\
\hline
\end{tabular}

Which matrix correctly represents Aliane's flight information?

\begin{tabular}{|c|c|c|c|c|}
\hline
& \textbf{A} & \textbf{B} & \textbf{C} & \textbf{D} \\
\hline
\textbf{A} & 0 & 4.2 & 3.9 & - \\
\hline
\textbf{B} & 5.1 & 0 & - & 9.5 \\
\hline
\textbf{C} & - & 1.7 & 0 & 2.2 \\
\hline
\textbf{D} & 10.5 & 8.6 & - & 0 \\
\hline
\end{tabular}



Answer :

To represent Aliane's flight information in a matrix, we need to organize the flight times between the cities in a systematic way. A flight matrix shows the flight times from each departing city to each arriving city.

Here, we will construct a 4x4 matrix for the cities A, B, C, and D, with rows representing the departing cities and columns representing the arriving cities.

### Step-by-Step Solution:

1. Determine the size of the matrix:
Since there are 4 cities (A, B, C, D), we will create a 4x4 matrix.

2. Initialize the matrix:
- Each entry [tex]\([i][j]\)[/tex] in the matrix will represent the flight time from city [tex]\(i\)[/tex] to city [tex]\(j\)[/tex].
- If there is no direct flight between the cities, we set the value to 0.

3. Update the matrix based on given flight times:
- From City A:
- To City B: 4.2 hours
- To City C: 3.9 hours
- From City B:
- To City A: 5.1 hours
- To City D: 9.5 hours
- From City C:
- To City B: 1.7 hours
- To City D: 2.2 hours
- From City D:
- To City A: 10.5 hours
- To City B: 8.6 hours

### Constructing the Flight Time Matrix:

Let's fill the matrix step by step:

```
Flight Matrix (Departing from rows, arriving at columns):
A B C D
A [[ 0, 4.2, 3.9, 0 ],
B [ 5.1, 0, 0, 9.5 ],
C [ 0, 1.7, 0, 2.2 ],
D [10.5, 8.6, 0, 0 ]]
```

So, the final flight time matrix is:

[tex]\[ \begin{matrix} & A & B & C & D \\ A & 0 & 4.2 & 3.9 & 0 \\ B & 5.1 & 0 & 0 & 9.5 \\ C & 0 & 1.7 & 0 & 2.2 \\ D & 10.5 & 8.6 & 0 & 0 \end{matrix} \][/tex]

Thus, the matrix that correctly represents Aliane's flight information is:

[tex]\[ \begin{bmatrix} 0 & 4.2 & 3.9 & 0 \\ 5.1 & 0 & 0 & 9.5 \\ 0 & 1.7 & 0 & 2.2 \\ 10.5 & 8.6 & 0 & 0 \end{bmatrix} \][/tex]