M.A.S (Most Affordable Speed) is defined as the speed

M.A.S (Most Affordable Speed) is defined as the speed where the fuel consumption of a car is the lowest.  The average family car consumes 3 liters of fuel per 36 kilometers at the M.A.S with only one passenger (the driver).  A pickup truck consumes twice as much as a family car does.  Assuming the fuel consumption of both cars rises by  % of the original consumption for each additional passenger, how many km per litter would a pickup truck do if the driver has three additional passengers?

(a) 10 km.
(b) 5.8 km.
(c) 6 km.
(d) 5.4 km.
(e) 4 km.

The best answer is D.
This is a question with a lot of dispensable text, it teaches us to focus on relevant information only. A family car consumes 1 liter for 12 Km, a pickup truck consumes twice as much, 1 liter for 6 Km. There are 3 additional passengers so the consumption rises by 10%, 6km*0.9 = 5.4km