A moving truck uses 28 gallons of diesel fuel in traveling 504 miles. In order for the truck to travel the same distance using 21 gallons of diesel fuel, by how many miles per gallon must the truck’s fuel mileage be increased?	Pick
A) 6 B) 10 C) 8 D) 12 E) 21
There are two sets 28G1 gallons and 21G2 gallons details given.   28 gallons covering 504 miles   Then 1 G1 is used to cover 18 miles.   Now for 21 G2 covering 504 miles.   then 1 G2 is used to cover 24 miles.   There must   24 - 18= 
<gadget id="calculator">  24 - 18</gadget>
<output>6</output>
6 miles per gallon increment is needed for 21 gallons to improve the mileage to cover 504 miles.   IMO 6 is correct answer.
<result>A</result>
A moving truck uses 28 gallons of diesel fuel in traveling 504 miles. In order for the truck to travel the same distance using 21 gallons of diesel fuel, by how many miles per gallon must the truck’s fuel mileage be increased?