BTGmoderatorLU wrote:A truck traveling at 70 MPH uses 30% more gasoline to travel a certain distance than at 50 MPH. If the truck can travel 19.5 miles on a liter of gasoline at 50 MPH, how far the truck can travel at 70 MPH on 10 liters of gasoline?

A. 100
B. 150
C. 175
D. 200
E. 125

We are given that the truck travels 19.5 miles on one liter of gasoline when traveling at 50 mph. Assuming the distance is 50 miles, then it uses 50/19.5 = 500/195 = 100/39 liters of gasoline to travel 50 miles. Since the truck use 30% more gasoline to travel the same distance at 70 mph than at 50 mph, the truck uses 100/39 x 1.3 = 130/39 = 10/3 liters of gasoline to travel 50 miles when traveling at 70 mph. Since 10/(10/3) = 3, the truck can travel 3 times the distance of 50 miles on 10 liters of gasoline; thus, the truck can travel 150 miles on 10 liters of gasoline when traveling at 70 mph.

Alternate Solution:

If the truck uses 30% more gasoline at 70 mph, then the truck will need 1.3 liters of gasoline to travel 19.5 miles at 70 mph. If 1.3 liters of gasoline is needed to travel 19.5 miles, the number of miles, say x, that can be traveled using 10 liters of gasoline can be found using the following proportion:

19.5/x = 1.3/10

1.3x = 195

13x = 1950

x = 150

Answer: B