GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 23 Oct 2019, 20:06

### 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

# Greg is training for a marathon by running to and from work each day,

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Senior RC Moderator
Joined: 02 Nov 2016
Posts: 4150
GPA: 3.39
Greg is training for a marathon by running to and from work each day,  [#permalink]

### Show Tags

02 Apr 2017, 12:33
1
00:00

Difficulty:

15% (low)

Question Stats:

80% (01:13) correct 20% (01:33) wrong based on 54 sessions

### HideShow timer Statistics

Greg is training for a marathon by running to and from work each day, a distance of 12 miles each way. He runs from home to work at an average speed of 6 miles per hour and returns at an average speed of 4 miles per hour. What is Greg’s average speed, in miles per hour, for the round trip?

A. 5.5
B. 5.0
C. 4.8
D. 2.5
E. 2.4

_________________
Senior Manager
Joined: 19 Apr 2016
Posts: 268
Location: India
GMAT 1: 570 Q48 V22
GMAT 2: 640 Q49 V28
GPA: 3.5
WE: Web Development (Computer Software)
Greg is training for a marathon by running to and from work each day,  [#permalink]

### Show Tags

02 Apr 2017, 12:42
Greg is training for a marathon by running to and from work each day, a distance of 12 miles each way. He runs from home to work at an average speed of 6 miles per hour and returns at an average speed of 4 miles per hour. What is Greg’s average speed, in miles per hour, for the round trip?

A. 5.5
B. 5.0
C. 4.8
D. 2.5
E. 2.4

for two given speeds x and y the avg speed is calculated as 2xy/(x+y)

so Greg’s average speed = 2*6*4/(6+4) = 48/10 = 4.8 mph

Hence option C is correct
Hit Kudos if you liked it
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8147
Location: United States (CA)
Re: Greg is training for a marathon by running to and from work each day,  [#permalink]

### Show Tags

04 Oct 2018, 19:40
Greg is training for a marathon by running to and from work each day, a distance of 12 miles each way. He runs from home to work at an average speed of 6 miles per hour and returns at an average speed of 4 miles per hour. What is Greg’s average speed, in miles per hour, for the round trip?

A. 5.5
B. 5.0
C. 4.8
D. 2.5
E. 2.4

We can use the formula: average rate = total distance/total time:

average rate = 24/(12/6 + 12/3) = 24/5 = 4.8

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Intern
Status: Applying
Joined: 24 Oct 2017
Posts: 31
Location: India
WE: Investment Banking (Investment Banking)
Re: Greg is training for a marathon by running to and from work each day,  [#permalink]

### Show Tags

05 Oct 2018, 03:23
1
It is common to solve a question such as this using logic that average speed should be average of two speeds, especially when the distance covered is the same. Right? Actually no.

The best way to solve such a question would be using the formula: (2*speed 1*speed 2) / (speed 1+ speed 2).

However, a slightly crude but effective technique that one can use ONLY if one is running out of time is to choose the option which is slightly less than the average of the speeds. This trick works only if the distance traveled is the same and if options give you a clear winner as it does in this case.

A) Greater than average: Incorrect
B) Equal to average: Incorrect
C) Slightly lesser than average: Correct
D) Way lesser than average: Incorrect
E) Way lesser than average: Incorrect

Hope this helps!
EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 15316
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: Greg is training for a marathon by running to and from work each day,  [#permalink]

### Show Tags

05 Oct 2018, 14:51
1
Hi All,

We're told that Greg is training for a marathon by running to and from work each day, a distance of 12 miles each way; he runs from home to work at an average speed of 6 miles per hour and returns at an average speed of 4 miles per hour. We're asked for Greg’s average speed, in miles per hour, for the round trip. This question can be solved in a couple of different ways. Sometimes the answer choices are 'spread out' in such a way that you can avoid almost all of the 'math' and use a 'logic shortcut' to get to the correct answer.

To start, since Greg is running the SAME distance in each direction, it will take him MORE time travel that distance at 4 miles/hour than it will take him to travel at 6 miles/hour. This makes this a 'Weighted Average' scenario - meaning that his average speed will be CLOSER to 4 miles/hour than it will be to 6 miles/hour. We can eliminate Answers A and B.

Since his speed never drops below 4 miles/hour, there's no way for his average speed to be less than that - so we can eliminate Answers D and E. There's only one answer remaining...

GMAT assassins aren't born, they're made,
Rich
_________________
Contact Rich at: Rich.C@empowergmat.com

The Course Used By GMAT Club Moderators To Earn 750+

souvik101990 Score: 760 Q50 V42 ★★★★★
ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★
Re: Greg is training for a marathon by running to and from work each day,   [#permalink] 05 Oct 2018, 14:51
Display posts from previous: Sort by

# Greg is training for a marathon by running to and from work each day,

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne