kilukilam wrote:

At a speed of 50 miles per hour, a certain car uses 1 gallon of gasoline every 30 miles. If the car starts with a full 12 gallon tank of gasoline and travels for 5 hours at 50 miles per hour, the amount of gasoline used would be what fraction of a full tank?

A. 3/25

B. 11/36

C. 7/12

D. 2/3

E. 25/36

We are given that a certain car has a rate of 30 miles per gallon. We are next told that the car starts with a 12-gallon tank and travels for 5 hours at 50 miles per hour.

Since distance = rate x time, we know the car traveled 50 x 5 = 250 miles. We can use the car’s rate and distance traveled to determine how many gallons were used.

Gallons used = distance/rate

Gallons used = 250/30 = 25/3

Finally, we need to determine the amount of gasoline used as a fraction of a full 12-gallon tank.

(25/3)/12 = (25/3) x (1/12) = 25/36

Answer: E

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