 It is currently 30 Nov 2020, 06:19 ### 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

#### Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here. # On a road trip, Kip drove one-quarter the distance  Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS: GRE Instructor Joined: 10 Apr 2015
Posts: 3909
Followers: 164

Kudos [?]: 4777  , given: 70

1
KUDOS
Expert's post 00:00

Question Stats: 73% (02:19) correct 26% (01:58) wrong based on 53 sessions
On a road trip, Kip drove one-quarter the distance at an average speed of v miles per hour, one-quarter the distance at an average speed of 2v miles per hour, one-quarter the distance at 4v miles per hour, and one-quarter the distance at 8v miles per hour. In terms of v, what was Kip’s average speed (in miles per hour) for the entire trip?

A) 15/4v
B) 15v/4
C) 32v/15
D) 4v/15
E) 15v/32
[Reveal] Spoiler: OA

_________________

Brent Hanneson – Creator of greenlighttestprep.com  Moderator  Joined: 07 Jan 2018
Posts: 697
Followers: 11

Kudos [?]: 785  , given: 88

2
KUDOS
There are 4 sections in this journey. Each 1/4 of Total.

Lets say total distance is x then, each distance would be $$\frac{1}{4}$$ $$*x$$

Speed for each of these four sectors from the 1st to 4th is as follows:

v miles per hour, 2v miles an hour, 4v miles an hour and 8v miles an hour.

To find the total time traveled we have to find the time spent on each of the 4 sectors and add them up.

Total time = $$\frac{1}{4v} * x + \frac{1}{8v} * x + \frac{1}{16v} * x + \frac{1}{32v} * x = \frac{15x}{32v}$$

Therefore average speed = $$\frac{Distance traveled}{time taken}$$ = $$\frac{x}{15x}$$ divided by 32v = $$\frac{32v}{15}$$
_________________

Need Practice? 20 Free GRE Quant Tests available for free with 20 Kudos GRE Instructor Joined: 10 Apr 2015
Posts: 3909
Followers: 164

Kudos [?]: 4777  , given: 70

1
KUDOS
Expert's post
GreenlightTestPrep wrote:
On a road trip, Kip drove one-quarter the distance at an average speed of v miles per hour, one-quarter the distance at an average speed of 2v miles per hour, one-quarter the distance at 4v miles per hour, and one-quarter the distance at 8v miles per hour. In terms of v, what was Kip’s average speed (in miles per hour) for the entire trip?

A) 15/4v
B) 15v/4
C) 32v/15
D) 4v/15
E) 15v/32

Since we aren't told the total distance, let's assign a nice value to the distance.
Let's say 32 miles = TOTAL distance.
So, each quarter = 8 miles

Average speed = total distance/total travel time
So, we must find the travel time for EACH QUARTER and add them together.

Time = distance/speed, so:
Time spent driving v mph = 8/v = 8/v
Time spent driving 2v mph = 8/2v = 4/v
Time spent driving 4v mph = 8/4v = 2/v
Time spent driving 8v mph = 8/8v = 1/v

TOTAL travel time = 8/v + 4/v + 2/v + 1/v
= 15/v

Average speed = total distance/total travel time
= 32/(15/v)
= (32)(v/15)
= 32v/15

Cheers,
Brent
_________________

Brent Hanneson – Creator of greenlighttestprep.com  Manager  Joined: 19 Nov 2018
Posts: 102
Followers: 0

Kudos [?]: 108  , given: 53

2
KUDOS
Here's how I did it.
Attachments daum_equation_1564699973447.png [ 100.68 KiB | Viewed 999 times ] Re: On a road trip, Kip drove one-quarter the distance   [#permalink] 01 Aug 2019, 14:54
Display posts from previous: Sort by

# On a road trip, Kip drove one-quarter the distance  Question banks Downloads My Bookmarks Reviews Important topics  Powered by phpBB © phpBB Group Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.