What is the average speed of the car in a travel of 180Km

Question

Q. What is the average speed of the car in a travel of 180Km
1) The car travelled 1st 120Km at 60Km/hr average speed
2) The car travelled last 120Km at 60Km/hr average speed

shahrukh · Answer

I would go for C. Coz all the distance is covered under both the statements. If the question had told that first and last say 50 km (any numbers whose total was less than the total distance,) then it would have been E. But here i have to go with C.
What is OA, is there some catch?

empanado · Answer

Average speed = Total distance / Total time

Statement 1.
We have total distance, but not total time.
Not Sufficient

Statement 2
We have total distance, but only a part of the time. 
Not Sufficient
 
Combined
We have total distance and total time. Sufficient. 

Answer is C.

parsifal · Answer

E

I can give you 2 possible solutions when the 2 statements are combined.

1. A constant speed of 60 Km/hr. In this case, the average speed is 60 km/hr

2. First 60 kms in 1/2 hour. 
 Second 60 kms in 1.5 hours. 
The last 60 kms again is travelled in 1/2 hour

Note that the first and last 120 kms are still covered in 2 hours giving the AVERAGE speed as 60

Now, 180 kms were travelled in 2.5 hours, hence avg speed = 72.
(Similarly, more solutions are possible)

Statements 1 and 2 combined cannot give you a conclusive answer. Hence E


best,
parsifal

What is the average speed of the car in a travel of 180Km

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