It is currently 17 Oct 2017, 20:47

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 cyclist travels 20 miles at a speed of 15 miles per hour.

Author Message
TAGS:

Hide Tags

Manager
Joined: 15 Apr 2012
Posts: 93

Kudos [?]: 60 [0], given: 134

Concentration: Technology, Entrepreneurship
GMAT 1: 460 Q38 V17
GPA: 3.56
A cyclist travels 20 miles at a speed of 15 miles per hour. [#permalink]

Show Tags

08 Jul 2012, 01:58
1
This post was
BOOKMARKED
00:00

Difficulty:

15% (low)

Question Stats:

79% (01:00) correct 21% (01:16) wrong based on 224 sessions

HideShow timer Statistics

A cyclist travels 20 miles at a speed of 15 miles per hour. If he returns along the same path and the entire trip takes 2 hours, at what speed did he return?

(A) 15 mph
(B) 20 mph
(C) 22 mph
(D) 30 mph
(E) 34 mph
[Reveal] Spoiler: OA

Last edited by Bunuel on 08 Jul 2012, 02:42, edited 1 time in total.
Edited the question.

Kudos [?]: 60 [0], given: 134

Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7670

Kudos [?]: 17338 [4], given: 232

Location: Pune, India
Re: A cyclist travels 20 miles at a speed of 15 miles per hour. [#permalink]

Show Tags

08 Jul 2012, 20:47
4
KUDOS
Expert's post
farukqmul wrote:
A cyclist travels 20 miles at a speed of 15 miles per hour. If he returns along the same path and the entire trip takes 2 hours, at what speed did he return?

(A) 15 mph
(B) 20 mph
(C) 22 mph
(D) 30 mph
(E) 34 mph

Let me add another method: Use logic!

He travels 20 miles at a speed of 15 mph so he takes 20/15 = 4/3 hrs to travel one way. Since total time is 2 hrs, he must have taken 2 - 4/3 = 2/3 hrs while returning.
Speed while returning = 20/(2/3) = 30 mph

(It's pretty much what cyberjadugar did but thinking in terms of equations can be a little frustrating during the test.)
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199 Veritas Prep Reviews Kudos [?]: 17338 [4], given: 232 Kellogg MMM ThreadMaster Joined: 29 Mar 2012 Posts: 322 Kudos [?]: 512 [2], given: 23 Location: India GMAT 1: 640 Q50 V26 GMAT 2: 660 Q50 V28 GMAT 3: 730 Q50 V38 Re: A cyclist travels 20 miles [#permalink] Show Tags 08 Jul 2012, 02:15 2 This post received KUDOS farukqmul wrote: A cyclist travels 20 miles at a speed of 15 miles per hour. If he returns along the same path and the entire trip takes 2 hours, at what speed did he return? (A) 15 mph (B) 20 mph (C) 22 mph (D) 30 mph (E) 34 mph Hi, we know that $$speed = \frac {distance}{time}$$ $$time(2hours) = \frac {20}{15}+\frac {20}{v}$$ or $$v= \frac {20}{2- \frac 43}$$ or $$v= 30$$ Thus, Answer (D) Regards, Kudos [?]: 512 [2], given: 23 Kaplan GMAT Instructor Joined: 25 Aug 2009 Posts: 644 Kudos [?]: 301 [0], given: 2 Location: Cambridge, MA Re: A cyclist travels 20 miles at a speed of 15 miles per hour. [#permalink] Show Tags 08 Jul 2012, 19:05 Cyberjadugar's math is dead on! There is another way to approach this problem, however--backsolving. Because the answers are numbers in ascending order, and because the task we are assigned is simple (not the same as easy! A speed is simple, the sum of the squares of two speeds would be complex), we can plug those numbers back into the task to see if they work. With backsolving, it's useful to start at B or D. This maximized our chances of getting the answer right on the first try. If B is too big, or if D is too small, then we immediately know that A or E is correct, respectively. But B clearly doesn't work here. The total distance traveled is 40 miles, and the total time is two hours. The average speed for the whole trip needs to be 40/2 = 20 mph, so 20 for only the second half won't cut it. Let's try (D). 20 miles at 15 miles/hour takes 4/3 of an hour. 20 miles at (D) 30 miles/hour takes half that time, 2/3 of an hour. So the whole trip takes 6/3 = 2 hours, just what we wanted! You may think, "How lucky!" but actually luck played no part. After all, what if we'd been wrong? Well, if we'd spend too little time making the trip, we'd have known that 30 was too fast. Since 20 was too slow, we could have marked (C) as correct without doing a bit of math! And similarly, if we'd been to slow even at 30, we could have just mark (E) and been done. Part of the power of backsolving as a strategy is the ability to use the answer choices as a powerful problem-solving tool. Good luck on your prep! _________________ Eli Meyer Kaplan Teacher http://www.kaptest.com/GMAT Prepare with Kaplan and save$150 on a course!

Kaplan Reviews

Kudos [?]: 301 [0], given: 2

Director
Status: Tutor - BrushMyQuant
Joined: 05 Apr 2011
Posts: 622

Kudos [?]: 763 [0], given: 59

Location: India
Concentration: Finance, Marketing
Schools: XLRI (A)
GMAT 1: 700 Q51 V31
GPA: 3
WE: Information Technology (Computer Software)
Re: A cyclist travels 20 miles at a speed of 15 miles per hour. [#permalink]

Show Tags

19 Jul 2012, 04:16
A cyclist travels 20 miles at a speed of 15 miles per hour

Time taken while going= Distance/Speed = 20/15 hrs = (4/3)hrs

Total time = 2hours

Time taken while returning = total - time taken while going = 2 - 4/3 = (2/3)hrs

Distance = 20miles
Time = (2/3)hrs

Speed = Distance/Time = 20/ (2/3) = 30 miles/hr

Hope it helps!
_________________

Ankit

Check my Tutoring Site -> Brush My Quant

GMAT Quant Tutor
How to start GMAT preparations?
How to Improve Quant Score?
Gmatclub Topic Tags
Check out my GMAT debrief

How to Solve :
Statistics || Reflection of a line || Remainder Problems || Inequalities

Kudos [?]: 763 [0], given: 59

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 16760

Kudos [?]: 273 [0], given: 0

Re: A cyclist travels 20 miles at a speed of 15 miles per hour. [#permalink]

Show Tags

23 Aug 2014, 20:53
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

Kudos [?]: 273 [0], given: 0

Re: A cyclist travels 20 miles at a speed of 15 miles per hour.   [#permalink] 23 Aug 2014, 20:53
Display posts from previous: Sort by