What was the average number of miles...

[swerve]

What was the average number of miles per gallon of gasoline for a car during a certanin trip?

1) The car used half of its 25-gallon tank for the 120 mile trip.
2) The cost of the gasoline used by the car for the tirp was $ 1.20 per gallon.

The OA is A.

Please, can any expert assist me with this DS question? I don't have it clear and I appreciate if any explain it for me. Thanks.

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Hi swerve,

We're asked for the average number of MILES per GALLON of gasoline for a car during a certain trip. While this prompt is a little different from a typical distance-rate-time question, the basic idea is still the same - to answer this question, we need information that will help to determine the ratio of miles driven to gallons of gasoline used.

1) The car used half of its 25-gallon tank for the 120 mile trip.

While Fact 1 is a bit 'oddly-worded', we're meant to deduce that 12.5 gallons of gas were used to drive the entire 120 miles. Thus, we have the necessary information to answer the question (and the answer would be 120/12.5).
Fact 1 is SUFFICIENT

2) The cost of the gasoline used by the car for the trip was $ 1.20 per gallon.

Fact 2 tells us nothing about the distance traveled or the number of gallons used.
Fact 2 is INSUFFICIENT

Final Answer: A

GMAT assassins aren't born, they're made,
Rich