Estimate the fuel consumption of cars in USA.

Clarifying questions:-

1.What does it mean by car ? are we talking about personal car or including government vehicles & public transport vehicle’s also.

Assuming that interviewer said for personal car.

2.We have to calculate fuel consumption daily/monthly/weekly?

Assuming here daily.

USA has a population of 20 cr.

Assuming that in a  family there is a 4 people.

Total families=20 cr/4=5 cr

% of family who can afford car.

Now, I am further going down to divide the group1 in 2 segmets- 1.power user                                                                                            2.casual user

Total distance=700+420

                         =1120 million km

Imagining that one car gives an average of 15 km per litre

So total  fuel consumption in litre=1120 million/15

                                                            =75 million litre

Converting it into barrel=75 million/160

                                           =5 lakh barrel daily