Bunuel wrote:

A certain truck uses 18 gallons of diesel fuel in traveling 270 miles. In order for the truck to travel the same distance using 10 gallons of diesel fuel, by how many miles per gallon must the truck’s fuel mileage be increased?

A. 8

B. 9

C. 12

D. 15

E. 27

There are two sets 18G1 gallons and 10G2 gallons details given.

18 gallons covering 270 miles

Then 1 G1 is used to cover 15 miles.

Now for 10 G2 covering 270 miles.

then 1 G2 is used to cover 27 miles.

There must 27 - 15 = 12 miles per gallon increment is needed for 10 gallons to improve the mileage to cover 270 miles.

IMO C is correct answer.

OA please...will correct if I missed anything..