Author 
Message 
TAGS:

Hide Tags

Director
Status: Finally Done. Admitted in Kellogg for 2015 intake
Joined: 25 Jun 2011
Posts: 537
Location: United Kingdom
Concentration: International Business, Strategy
GPA: 2.9
WE: Information Technology (Consulting)

If a car traveled from Townsend to Smallville at an average [#permalink]
Show Tags
07 Nov 2011, 14:46
1
This post received KUDOS
15
This post was BOOKMARKED
Question Stats:
69% (02:01) correct
31% (01:04) wrong based on 597 sessions
HideShow timer Statistics
If a car traveled from Townsend to Smallville at an average speed of 40 mph and then returned to Townsend later that evening, what was the average speed for the entire trip? (1) The trip from Townsend to Smallville took 50% longer than the trip from Smallville to Townsend. (2) The distance from Townsend to Smallville is 165 miles. How can the answer be A folks?
Official Answer and Stats are available only to registered users. Register/ Login.
_________________
Best Regards, E.
MGMAT 1 > 530 MGMAT 2> 640 MGMAT 3 > 610 GMAT ==> 730



Intern
Joined: 30 Jun 2011
Posts: 12
Location: Virginia, USA

Re: Townsend to Smallville [#permalink]
Show Tags
07 Nov 2011, 16:03
3
This post received KUDOS
enigma123 wrote: If a car traveled from Townsend to Smallville at an average speed of 40 mph and then returned to Townsend later that evening, what was the average speed for the entire trip?
(1) The trip from Townsend to Smallville took 50% longer than the trip from Smallville to Townsend. (2) The distance from Townsend to Smallville is 165 miles.
How can the answer be A folks? Lets distance be x miles between 2 cities (lets say T and S). From T to S speed = 40 mph so time taken = x/40 hrs From S to T spees = 60 mph (50% less time) so time taken = x/60 hrs Total time taken = x/40 + x/60 = x/24 hrs Total distance travelled = 2x miles So avg speed = 2x/(x/24) = 48 mph Instead of x you can solve this by taking 40 miles as distance. So statement 1 is sufficient.



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7440
Location: Pune, India

Re: Townsend to Smallville [#permalink]
Show Tags
08 Nov 2011, 10:30
8
This post received KUDOS
Expert's post
12
This post was BOOKMARKED
enigma123 wrote: If a car traveled from Townsend to Smallville at an average speed of 40 mph and then returned to Townsend later that evening, what was the average speed for the entire trip?
(1) The trip from Townsend to Smallville took 50% longer than the trip from Smallville to Townsend. (2) The distance from Townsend to Smallville is 165 miles.
How can the answer be A folks? A couple of basics: 1. Average Speed = Total Distance/ Total Time2. Average Speed = Weighted Average of different speeds where ' time taken' is the weight 3. If equal distances (say d) are traveled at different speeds, a and b, average speed = 2d/[d/a + d/b] = 2ab/(a+b) In this case, average speed is independent of 'd', the distance. 4. If speeds a and b are maintained for equal time intervals, say t, average speed = (at+bt)/2t = (a+b)/2 In this case, average speed is independent of 't', the time interval. Given: Car travels equal distances. Speed in first case is 40 mph. We need the speed in the second case to get the average speed (given by 2*40*b/(40+b)) (1) Ratio of time in the two cases T to S: S to T= 3:2 Then ratio of speed in the two cases = 2:3 We know the speed from T to S = 40 Then speed from S to T must be 60 Since we have the value of b (= 60) i.e. the speed while coming back, we can easily find the average speed.. Sufficient. (2) As we discussed, distance traveled doesn't affect average speed in this case. Not sufficient Answer (A)
_________________
Karishma Veritas Prep  GMAT Instructor My Blog
Get started with Veritas Prep GMAT On Demand for $199
Veritas Prep Reviews



Director
Joined: 29 Nov 2012
Posts: 878

If a car traveled from Townsend to Smallville at an average [#permalink]
Show Tags
11 Jul 2013, 08:38
If a car travelled from Townsend to Smallville at an average speed of 40 mph and then returned to Townsend along the same route later that evening, what was the average speed for the entire trip? (1) The trip from Townsend to Smallville took 50% longer than the trip from Smallville to Townsend. (2) The route between Townsend and Smallville is 165 miles long. Can someone provide a detailed analysis for statement A. Thanks
_________________
Click +1 Kudos if my post helped...
Amazing Free video explanation for all Quant questions from OG 13 and much more http://www.gmatquantum.com/og13th/
GMAT Prep software What if scenarios http://gmatclub.com/forum/gmatprepsoftwareanalysisandwhatifscenarios146146.html



Director
Joined: 14 Dec 2012
Posts: 832
Location: India
Concentration: General Management, Operations
GPA: 3.6

Re: If a car traveled from Townsend to Smallville at an average [#permalink]
Show Tags
11 Jul 2013, 08:48
1
This post received KUDOS
fozzzy wrote: Can someone provide a detailed analysis for statement A. Thanks hi, let say distance between T and S be X miles time take to cover from TS=X/40 statement 1==> time for TS=1.5( time from ST) THEREFORE==>X/40=1.5(T) THEREFORE ==>T=X/60 Average speed =total dist/total time==>total dist=X+X=2X AVG SPEED=2X/(X/40+X/60)=48 HENCE SUFFICIENT. HOPE IT HELPS
_________________
When you want to succeed as bad as you want to breathe ...then you will be successfull....
GIVE VALUE TO OFFICIAL QUESTIONS...
GMAT RCs VOCABULARY LIST: http://gmatclub.com/forum/vocabularylistforgmatreadingcomprehension155228.html learn AWA writing techniques while watching video : http://www.gmatprepnow.com/module/gmatanalyticalwritingassessment : http://www.youtube.com/watch?v=APt9ITygGss
Last edited by blueseas on 11 Jul 2013, 08:58, edited 1 time in total.



Math Expert
Joined: 02 Sep 2009
Posts: 39656

Re: If a car traveled from Townsend to Smallville at an average [#permalink]
Show Tags
11 Jul 2013, 08:55
2
This post received KUDOS
Expert's post
3
This post was BOOKMARKED
If a car travelled from Townsend to Smallville at an average speed of 40 mph and then returned to Townsend along the same route later that evening, what was the average speed for the entire trip?(1) The trip from Townsend to Smallville took 50% longer than the trip from Smallville to Townsend. Time from T to S 3/2 of that from S to T, thus Speed from T to S 2/3 of that from S to T. Thus speed from S to T = 60 mph. Now, \(( average \ speed)=\frac{(total \ distance)}{(total \ time)}=\frac{2d}{\frac{d}{40}+\frac{d}{60}}\), where d is the distance between S and T > d reduces > we can get the average time. Sufficient. (2) The route between Townsend and Smallville is 165 miles long. We know nothing about the speed from S to T. Not sufficient. Answer: A. Hope it's clear.
_________________
New to the Math Forum? Please read this: All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Math Expert
Joined: 02 Sep 2009
Posts: 39656

Re: If a car traveled from Townsend to Smallville at an average [#permalink]
Show Tags
11 Jul 2013, 08:56



Director
Joined: 14 Dec 2012
Posts: 832
Location: India
Concentration: General Management, Operations
GPA: 3.6

Re: If a car traveled from Townsend to Smallville at an average [#permalink]
Show Tags
11 Jul 2013, 08:59
Bunuel wrote: []
Small correction: the average speed would be 48 mph, not 50. thanks bunuel
_________________
When you want to succeed as bad as you want to breathe ...then you will be successfull....
GIVE VALUE TO OFFICIAL QUESTIONS...
GMAT RCs VOCABULARY LIST: http://gmatclub.com/forum/vocabularylistforgmatreadingcomprehension155228.html learn AWA writing techniques while watching video : http://www.gmatprepnow.com/module/gmatanalyticalwritingassessment : http://www.youtube.com/watch?v=APt9ITygGss



Senior Manager
Joined: 13 May 2013
Posts: 469

Re: If a car traveled from Townsend to Smallville at an average [#permalink]
Show Tags
29 Jul 2013, 12:26
1
This post was BOOKMARKED
If a car travelled from Townsend to Smallville at an average speed of 40 mph and then returned to Townsend along the same route later that evening, what was the average speed for the entire trip?
Distance/Time = average speed
D/T = 40
(1) The trip from Townsend to Smallville took 50% longer than the trip from Smallville to Townsend.
We're looking for the total time here. In other words, we want to know the total distance/total time (the distance to and from and the speed to and from) We know that the distance is the same for both trips so that can be represented as 2d. Because we don't know the distance, to find time we will have to get distance/speed = time.
Total distance = 2d Total time = time from T to S = time from S to T. Time = distance/speed. We know that the speed from T to S was 50% more than from S to T which means that the speed from S to T was 50% greater (i.e. 40 + 40*.5 = 60MPH)
Total Distance/Total Time = total average 2d/([d/40] + [d/60]) = total average 2d/([3d/120 + [2d/120]) = total average 2d/(5d/120) = total average 2d * 120/5d 240d/5d d=48
If we plug 48 into d/t = 40 then we can get a value for t. SUFFICIENT
(2) The route between Townsend and Smallville is 165 miles long. We know that the distance is 165 which means that the round trip is 330 miles. The problem is, we are looking for average speed and we have no idea what speed was done on the return trip. INSUFFICIENT
(B)



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15946

Re: If a car traveled from Townsend to Smallville at an average [#permalink]
Show Tags
19 Nov 2013, 22:29
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.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15946

Re: If a car traveled from Townsend to Smallville at an average [#permalink]
Show Tags
26 Nov 2014, 03:03
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.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15946

Re: If a car traveled from Townsend to Smallville at an average [#permalink]
Show Tags
08 Jan 2016, 06:52
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.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



Intern
Joined: 05 May 2016
Posts: 8
Location: India

If a car traveled from Townsend to Smallville at an average [#permalink]
Show Tags
06 May 2016, 14:30
VeritasPrepKarishmaIf a car traveled from Townsend to Smallville at an average speed of 40 mph and then returned to Townsend later that evening, what was the average speed for the entire trip? (1) The trip from Townsend to Smallville took 50% longer than the trip from Smallville to Townsend. (2) The distance from Townsend to Smallville is 165 miles. How can the answer be A folks? mam in this you said Ratio of time in the two cases T to S: S to T= 3:2 how mam? can u explain in bit detail plz?



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7440
Location: Pune, India

Re: If a car traveled from Townsend to Smallville at an average [#permalink]
Show Tags
07 May 2016, 05:29
The trip from T to S took 50% longer. So if trip from S to T took 2 hrs, the trip from T to S took 50% more that is 50% of 2 hrs more i.e. 1 hour extra. So it took 2+1 hours i.e. 3 hrs. This gives a ratio of 3:2. Time taken from T to S : Time taken from S to T. The actual time taken could be anything. 6 hrs and 4 hrs or 9 hrs and 6 hrs etc. Posted from my mobile device
_________________
Karishma Veritas Prep  GMAT Instructor My Blog
Get started with Veritas Prep GMAT On Demand for $199
Veritas Prep Reviews



Manager
Joined: 22 Feb 2016
Posts: 111
Location: India
Concentration: Economics, Healthcare
GMAT 1: 690 Q42 V47 GMAT 2: 710 Q47 V39
GPA: 3.57

Re: If a car traveled from Townsend to Smallville at an average [#permalink]
Show Tags
26 Oct 2016, 08:22
Even I used to be confused with this concept but a through reading of speed time concept from magoosh helped me clear my basic flaws in understanding. Coming to the question: Speed distance has just one killer concept s=d/t Which means s is inversely proportional to time. now it is given t1=1.5t2 therefore s1 which is inversely proportional will be 2/3s2 s1=40 hence s2=60 Apply the average speed formula 2d/(d/40+d/60) take d common and cancel it . Voila! you got the answer Please give a kudos if you liked my answer.



Manager
Joined: 14 Oct 2012
Posts: 126

Re: If a car traveled from Townsend to Smallville at an average [#permalink]
Show Tags
24 Apr 2017, 17:59
my 2 cents:
Attachments
001.jpg [ 283.16 KiB  Viewed 398 times ]




Re: If a car traveled from Townsend to Smallville at an average
[#permalink]
24 Apr 2017, 17:59







