The distance between Omaha and Lincoln is 60 miles. John drives a car that gets 30 miles per gallon of gas, and David drives a car that gets 20 miles per gallon. How many more gallons of gas does David use on a round trip from Omaha to Lincoln?	Choose one:
A) 2 B) 3 C) 4 D) 5 E) 6
Ratio of John Car efficiency : David Car efficiency = 30:20   Round trip takes 120 miles. Hence converting any one of the base for 120 = 180:120   Means if David travel 120 miles for the same gallons Omaha travled 180 miles. The gallon required to travel extra 60 miles is   Hence = 60/30= 
<gadget id="calculator">60/30</gadget>
<output>2</output>
2   2nswer : 2
<result>A</result>
The distance between Omaha and Lincoln is 60 miles. John drives a car that gets 30 miles per gallon of gas, and David drives a car that gets 20 miles per gallon. How many more gallons of gas does David use on a round trip from Omaha to Lincoln?