Answer:
The mean would increase by 3
Explanation:
The number cars and their probability is shown on the first uploaded image
The mean for the number of cars[X] owned can be mathematically represented as
![E(x) = \sum [ x P(x= x)]](https://img.qammunity.org/2021/formulas/mathematics/college/9fj0tzpqcwfd48ak7pr414tiexxj37c5dd.png)
From the question we are told that each household purchased additional three cars
Let Z be the random variable for the number of cars when the the additional car where added
So Mathematically
Z = X + 3
The mean for the number of cars[X + 3] owned can be mathematically represented as
![E(Z)= E(X +3) = \sum [ (x+3) P(X= x)]](https://img.qammunity.org/2021/formulas/mathematics/college/s2hivrsuxlyrweo6xkfu4pu4xp2gui92xg.png)


From the above equation we can see that the mean would increase by factor of 3