Answer:

Step-by-step explanation:
The distance formula is given by:

We are given the two points (4, -1) and (a, 5). The distance between them is 10.
Let (4, -1) be (x₁, y₁) and let (a, 5) be (x₂, y₂). Substitute:

Solve for <em>a</em>. Square both sides and simplify:

Simplify:

Take the square root of both sides. Since we are taking an even root, we will need plus/minus. Hence:

Solve for <em>a:</em>
<em />
<em />
<em />
So, our two possible points are (12, 5) or (-4, 5).
Using the z-distribution, it is found that the smallest sample size required is given by:
B) 7 vehicles.
<h3>What is the margin of error for a z-distribution confidence interval?</h3>
It is given by:

In which:
is the population standard deviation.
In this problem, we have a 90% confidence level, hence
, z is the value of Z that has a p-value of
, so the critical value is z = 1.645.
The margin of error and the population standard deviation are given by, respectively:
.
Then, we solve for n to find the needed sample size.






Rounding up, 7 vehicles have to be sampled, hence option B is correct.
More can be learned about the z-distribution at brainly.com/question/25890103
He could do it 12 by 12 by 12 or 6 by 6 by 6 by 6 by 6 by 6 or he could do it 3 by 3 (the number of threes is double of 6