Question

The mileage of a vehicle at a speed of 50 kmph is 60 kmpl. If the speed is above 50 kmph, for every rise of 5 kmph in speed, the mileage decreases by 2 kmpl. If a man travels 300 km at a uniform speed, how many litres of petrol will the vehicle consume?

Statement 1: He travels a distance of 300 km at a uniform speed of 75 kmph.
Statement 2: The mileage of the vehicle at a speed of 75 kmph is 50 kmpl.

• A. If the data in statement (1) alone is sufficient to answer the question, but the data in statement (2) alone is not sufficient.
• B. If the data in statement (2) alone is sufficient to answer the question, but the data in statement (1) alone is not sufficient.
• C. If the data in both the statements together are needed to answer the question.
• D. If either statement (1) alone or statement (2) alone is sufficient to answer the question.
• E. If the data in neither statement (1) nor statement (2) is sufficient to answer the question, and more data is needed.

Hint:

Convert speed to mileage using the step-wise rule (5 kmph rise = 2 kmpl drop), then fuel = distance / mileage.

Answer 1

The Correct Option is D

Fuel consumed = distance / mileage = 300 / mileage. To answer the question we need to know the mileage that applies to this particular 300 km trip.

Statement 1 tells us the trip was made at a uniform 75 kmph. The rise from 50 kmph to 75 kmph is 25 kmph, which is five steps of 5 kmph each. Each step reduces mileage by 2 kmpl, so total reduction is 5 x 2 = 10 kmpl, giving a trip mileage of 60 - 10 = 50 kmpl. Fuel used = 300/50 = 6 litres. Statement 1 alone is sufficient.

Statement 2 directly states the mileage that applied during this trip: 50 kmpl at the speed he was driving (75 kmph). Using this mileage figure straightaway, fuel used = 300/50 = 6 litres, the same answer as above. Statement 2 alone is also sufficient.

Since each statement independently lets us compute the same fuel consumption of 6 litres, the answer is (d) - either statement alone is sufficient.