Answer:
<em>The sample size 'n' = 721</em>
<em>Number of cars 'n' = 721</em>
Step-by-step explanation:
<u><em>Explanation</em></u>:-
<em>Given Population proportion 'p' = 0.40</em>
<em>Given Margin of error = 0.03</em>
<em>90% of level of significance </em>
<em> </em>
<em></em>
<em>The Margin of error is determined by</em>
<em></em>
<em></em>

on calculation , we get
0.03√n = 0.8058

squaring on both sides , we get
n = 721.45≅721
<u><em>conclusion</em></u>:-
<em>The sample size 'n' = 721</em>
<em>Number of cars 'n' = 721</em>