Assume that the taxes on petrol is 125% of the price of petrol per litre as received by the retailer minus the taxes. If in the last week, the petrol prices per litre as received by the retailer minus the taxes was 35, 34, 35.5, 37, 37.5 and 38, the average amount of tax collected per litre of petrol is

Sum of all (Petrol price per litre - taxes) in the last week = 35+34+35.5+37+37.5+38

=  217

Taxes on petrol = 1.25 times (the price of petrol - taxes)

2.25* taxes on petrol = 1.25 times the price of petrol

The price of petrol = 1.8 times the taxes on petrol.

1.8 times the taxes on petrol - taxes on petrol = 217

0.8 times the taxes on petrol = 217

Taxes on petrol = $$\ \frac{217}{0.8}$$ = 271.25

The average amount of tax collected = $$\ \frac{271.25}{6}$$ 

= 45.2

A is the correct answer.