2. The table below shows the number of survey subjects who have received and not received a speeding ticket in the last year, and the color of their car.

\begin{tabular}{|l|l|l|}
\hline
& Speeding Ticket & No Speeding Ticket \\
\hline
Red Car & 15 & 135 \\
\hline
Not Red Car & 45 & 470 \\
\hline
\end{tabular}

a. Find the probability that a randomly chosen person has a speeding ticket or has a red car.

b. If two people are randomly chosen, find the probability that they both have a red car.



Answer :

Sure, let's go through this step-by-step.

### Given Data:
- Red Car with Speeding Ticket: 15
- Red Car without Speeding Ticket: 135
- Not Red Car with Speeding Ticket: 45
- Not Red Car without Speeding Ticket: 470

### Total number of people:
To find the total number of people surveyed, sum up all the values in the table:

[tex]\[ \text{Total People} = 15 + 135 + 45 + 470 = 665 \][/tex]

### Step-by-Step Calculation:

#### Part (a): Probability of a Speeding Ticket or Having a Red Car
We need to find the probability of a person either having a speeding ticket or having a red car.

1. Probability of having a Speeding Ticket:

[tex]\[ P(\text{Speeding Ticket}) = \frac{\text{Number with Speeding Ticket}}{\text{Total People}} = \frac{15 + 45}{665} = \frac{60}{665} \][/tex]

2. Probability of having a Red Car:

[tex]\[ P(\text{Red Car}) = \frac{\text{Number of Red Cars}}{\text{Total People}} = \frac{15 + 135}{665} = \frac{150}{665} \][/tex]

3. Probability of having both a Speeding Ticket and a Red Car (since we counted these people twice above):

[tex]\[ P(\text{Speeding Ticket and Red Car}) = \frac{15}{665} \][/tex]

4. Combined Probability (using the formula for the union of two events):

[tex]\[ P(\text{Speeding Ticket or Red Car}) = P(\text{Speeding Ticket}) + P(\text{Red Car}) - P(\text{Speeding Ticket and Red Car}) \][/tex]

Plugging in the numbers:

[tex]\[ P(\text{Speeding Ticket or Red Car}) = \frac{60}{665} + \frac{150}{665} - \frac{15}{665} = \frac{195}{665} - \frac{15}{665} = \frac{180}{665} \][/tex]

[tex]\[ P(\text{Speeding Ticket or Red Car}) \approx 0.2932 \][/tex]

Thus, the probability that a randomly chosen person has either a speeding ticket or a red car is approximately 0.2932.

#### Part (b): Probability that Two Randomly Chosen People Both Have a Red Car
We need to find the probability that two randomly chosen people both have a red car.

1. Probability that the first person has a Red Car:

[tex]\[ P(\text{First person has a Red Car}) = \frac{150}{665} \][/tex]

2. Probability that the second person, given the first is already chosen, also has a Red Car:

If the first person chosen has a red car, then there are [tex]\(150 - 1 = 149\)[/tex] red cars left out of [tex]\(665 - 1 = 664\)[/tex] people left.

[tex]\[ P(\text{Second person has a Red Car | first person has a Red Car}) = \frac{149}{664} \][/tex]

3. Combined Probability:

[tex]\[ P(\text{Both people have a Red Car}) = \frac{150}{665} \times \frac{149}{664} \][/tex]

[tex]\[ P(\text{Both people have a Red Car}) \approx 0.0505 \][/tex]

Thus, the probability that two randomly chosen people both have a red car is approximately 0.0505.