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 18 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 the most appropriate option:
A) 13	B) 13.5	C) 14	D) 14.5	E) 15
Ans is 14.5   Given d_ab = 2*d_bc   let d_ab = d and d_bc = x so d=2x   for average miles per gallon = (d+x)/((d/10)+(x/18)) = 14.5 (formula avg speed = total distance/ total time)
<result>D</result>
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 18 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?