Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 28 Jun 2016, 05:04

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

A boat leaves a town and travels to another town at an

Author Message
Senior Manager
Joined: 04 Mar 2007
Posts: 440
Followers: 2

Kudos [?]: 31 [0], given: 0

A boat leaves a town and travels to another town at an [#permalink]

Show Tags

14 Jun 2007, 09:15
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

A boat leaves a town and travels to another town at an average speed of 6 miles per hour. It returnes back at an average speed of 9 miles per hour. What is the average speed for the round-trip?

A) 7.1
B) 7.2
C) 7.3
D) 7.4
E) 7.5
Manager
Joined: 12 Apr 2007
Posts: 170
Followers: 1

Kudos [?]: 9 [0], given: 0

Show Tags

14 Jun 2007, 10:08
Because the first trip is only at 6 mph and the second trip is at 9 mph, the first trip takes 3/2 longer than the second trip...

so [6(3) + 9(2)]/5 = 7.2

think of it like a weighted average
CEO
Joined: 17 May 2007
Posts: 2989
Followers: 60

Kudos [?]: 531 [0], given: 210

Show Tags

14 Jun 2007, 22:16
Yup it is B. Another quick way to do this would be to assume that the distance between the towns is 18 miles.

Then time1= 3 hours and time 2 = 2 hours

Total D = 36 / total t = 5 = 36/5 = 7.2
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5062
Location: Singapore
Followers: 29

Kudos [?]: 281 [0], given: 0

Show Tags

14 Jun 2007, 22:47
Let the distance between the towns be x miles.

Time taken to the town = x/6 hours
Time taken to return = x/9

Average speed = 2x/(x+6 + x/9) = 7.2 miles/hr
Display posts from previous: Sort by