A certain car traveled twice as many miles from Town A to Town B as it did from Town B to Town C. From Town A to Town B, the car averaged 10 miles per gallon, and from Town B to Town C, the car averaged 12 miles per gallon. What is the average miles per gallon that the car achieved on its trip from Town A through Town B to Town C?	Choose one.
A) 11.5
B) 9.5
C) 13.5
D) 10.6
E) 14.5

Rationale: "step 1 ) took lcm of 10 and 12 . . came as 30 . just multiplied by 10 . . . ( to make easy calculation ) step 2 ) 300 distance between b to c . . . do 300 / 12 hence 25 gallons used step 3 ) twice distance . . hence 300 * 2 = 600 . . . do as above . . 600 / 10 = 60 gallons used step 4 ) total gallons . . 25 + 60 = 85 gallons step ) total miles = 300 + 600 = 900 miles hence . . average of whole journey = 900 / 85 which comes to 10.6 answer : d"
Answer: D