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Avg Speed

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by vittalgmat » Fri Jan 02, 2009 6:33 pm
It took the bus three hours to get from town A to town B. What was the average speed of the bus for the entire trip?

1. During the first hour the bus finished 1/3rd of the distance going at 60 km/h
2. During the second hour the average speed of the bus was 120 km/h, twice its speed during the third hour

[spoiler]OA: A
[/spoiler]
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Source: — Data Sufficiency |

by cramya » Fri Jan 02, 2009 6:42 pm
Avg speed = Total Distance /Total time taken

= Total Distance /3

Let Total Distance =d

Stmt I

For fist hour
speed * time = Distance
60 * 1 = d/3

can find d and then average speed.

SUFF


Stmt II

gives the speed in the 2nd and 3rd hour. No idea what it is in the first hour and hence the avg speed may changesince more or less distance may be covered in the first hour

INSUFF

Choose A)
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by vivek.kapoor83 » Sun Jan 04, 2009 10:07 am
same reason as cramya
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