Probability - Airplane row or column

Question

Airplane seats are labeled using 1-30 and A-F. What's the probability of your seat being in column A or row 30 ? Please help with steps to solve this.

Answer 1

First of all we need to find the number of seats on the plane. We have 30 rows and each row contains 6 seats (A-F).

$30\times 6=180$

In column A there are 30 seats (1 seat per row), and in row 30 there are 6 seats. But since we already counted seat 30A, we don't count it. So there is a 35 in 180 chance of your seat being in one of column A or row 30.

$\frac{35}{180} = \frac{7}{36} = 19.44 $%

Answer 2

There are $30$ rows and $6$ columns, which make for a total of $30 \cdot 6 = 180$ seats. Quite a small plane. Anyways, there are $6$ seats in row $30$, and $30$ seats in column A. But we have to consider the seat $30A$, as we are counting it twice. So we have $30+6-1=35$.

Out of $180$ possible seats, we want to be seated in $35$.

\begin{align} P(\text{Row $30$} ~\cup \text{Column A}) & = \frac{35}{180}\\ & = 0.19\overline4\\ & = 19.\overline4 \% \\ \end{align}