The Solution:
Given:
[tex]\begin{gathered} x=4000 \\ \\ \mu=3550 \\ \\ \sigma=870 \end{gathered}[/tex]
Applying the Z-statistic formula:
[tex]Z=\frac{x-\mu}{\sigma}=\frac{4000-3550}{870}=0.51724[/tex]
From the Z-scores tables:
The approximate probability of having a car weight that is more than 4000 pounds is:
[tex]P(x>4000)=0.30249[/tex]
Converting the above probability to percent, we have:
[tex]0.30249\times100=30.249\approx30\text{\%}[/tex]
Therefore, the correct answer is [ option D ]
