Author 
Message 
TAGS:

Hide Tags

Retired Moderator
Joined: 29 Oct 2013
Posts: 272
Concentration: Finance
GPA: 3.7
WE: Corporate Finance (Retail Banking)

A train traveled from Station A to Station B at an average speed of 80
[#permalink]
Show Tags
Updated on: 08 Jun 2015, 02:59
Question Stats:
65% (01:24) correct 35% (01:25) wrong based on 634 sessions
HideShow timer Statistics
A train traveled from Station A to Station B at an average speed of 80 kilometers per hour and then from Station B to Station C at an average speed of 60 kilometers per hour. If the train did not stop at Station B, what was the average speed at which the train traveled from Station A to C? (1) The distance that the train traveled from Station A to Station B was 4 times the distance that train traveled from Station B to Station C. (2) The amount of time it took to the train to travel from Station A to Station B is 3 times the amount of time that it took the train to travel from Station B to Station C. Attachment:
Screen_Shot_2012_05_15_at_8_48_47_PM.png [ 29.93 KiB  Viewed 9240 times ]
Official Answer and Stats are available only to registered users. Register/ Login.
_________________
Please contact me for super inexpensive quality private tutoring
My journey V46 and 750 > http://gmatclub.com/forum/myjourneyto46onverbal750overall171722.html#p1367876
Originally posted by NoHalfMeasures on 05 Jun 2014, 00:00.
Last edited by Bunuel on 08 Jun 2015, 02:59, edited 2 times in total.
Renamed the topic and edited the question.




Manager
Joined: 26 Dec 2011
Posts: 116

Re: A train traveled from Station A to Station B at an average speed of 80
[#permalink]
Show Tags
05 Jul 2016, 00:50
NoHalfMeasures wrote: A train traveled from Station A to Station B at an average speed of 80 kilometers per hour and then from Station B to Station C at an average speed of 60 kilometers per hour. If the train did not stop at Station B, what was the average speed at which the train traveled from Station A to C? (1) The distance that the train traveled from Station A to Station B was 4 times the distance that train traveled from Station B to Station C. (2) The amount of time it took to the train to travel from Station A to Station B is 3 times the amount of time that it took the train to travel from Station B to Station C. Attachment: The attachment Screen_Shot_2012_05_15_at_8_48_47_PM.png is no longer available The clear way to handle this answer 
Attachments
Untitled.jpg [ 58.85 KiB  Viewed 6843 times ]
_________________
Thanks, Kudos Please




Senior Manager
Joined: 13 Jun 2013
Posts: 277

Re: A train traveled from Station A to Station B at an average speed of 80
[#permalink]
Show Tags
05 Jun 2014, 01:29
MensaNumber wrote: A train traveled from station A to station B at an average speed of 80 kmph and then from Station B to Station C at an average speed of 60 kmph. What was the average speed from A to C?
1. The distance from A to C four times the distance from B to C 2. The amount of time it took to travel from A to B is four time that of time it took to travel from B to C
Kudos if you liked the question Average speed = total distance/ total time. 1) ABC let bc=x, therefore AC=4x, and AB=3x thus average speed = 4x/{(3x/80)+(x/60)} we can easily calculate the value of avg. speed from the above exp. hence sufficient 2) ABc let distance between AB=x and BC=y x/80=4(y/60) x=(16/3)y1) average speed = x+y/{(x/80)+(y/60)} we can substitute the value of x in terms of y in the above expression to find out the average speed. hence sufficient therefore correct answer should be D



Intern
Joined: 02 Jan 2015
Posts: 32
GMAT Date: 02082015
GPA: 3.7
WE: Management Consulting (Consulting)

Re: A train traveled from Station A to Station B at an average speed of 80
[#permalink]
Show Tags
06 Jun 2015, 05:40
Is there a quicker way to see that the distance variable cancels out, rather than going through the entire algebraic calculation? I made the assumption that the variable would remain, and struggle to finish in ~ 2 minutes once I start getting into algebra for DS questions. Thanks..



Math Expert
Joined: 02 Aug 2009
Posts: 6535

Re: A train traveled from Station A to Station B at an average speed of 80
[#permalink]
Show Tags
06 Jun 2015, 07:38
ElCorazon wrote: Is there a quicker way to see that the distance variable cancels out, rather than going through the entire algebraic calculation? I made the assumption that the variable would remain, and struggle to finish in ~ 2 minutes once I start getting into algebra for DS questions. Thanks.. Hi ElCorazon, the Q stem tells us the speed in two different routes and asks us the average speed.. for this we require the distance or the ratio of distances.. lets see the statement.. 1)statement 1 gives us the ratio of distance .. so sufficient.. 2) statement two tells us the ratio of time so multiplying this ratio with speed would give us the ratio of distance .. again sufficient ans D
_________________
1) Absolute modulus : http://gmatclub.com/forum/absolutemodulusabetterunderstanding210849.html#p1622372 2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html 3) effects of arithmetic operations : https://gmatclub.com/forum/effectsofarithmeticoperationsonfractions269413.html
GMAT online Tutor



EMPOWERgmat Instructor
Status: GMAT Assassin/CoFounder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 12183
Location: United States (CA)

Re: A train traveled from Station A to Station B at an average speed of 80
[#permalink]
Show Tags
06 Jun 2015, 11:51
Hi ElCorazon, The 'goal' to try to answer each Quant question in under 2 minutes is NOT practical. While some questions can be solved relatively quickly (in under 30 seconds), certain questions are designed to take longer to solve (upwards of 3 minutes, and that's if you KNOW what you're doing). These types of "multistep trip" questions are usually wordier, take more steps to solve and require a higher degree of organization and attentiontodetail than most prompts, so it's understandable that you would need MORE than 2 minutes to solve it. Instead of having a "2 minutes or less" goal, focus more on your overall efficiency  you should try to get this question correct without wasting time. GMAT assassins aren't born, they're made, Rich
_________________
760+: Learn What GMAT Assassins Do to Score at the Highest Levels Contact Rich at: Rich.C@empowergmat.com
Rich Cohen
CoFounder & GMAT Assassin
Special Offer: Save $75 + GMAT Club Tests Free
Official GMAT Exam Packs + 70 Pt. Improvement Guarantee www.empowergmat.com/
***********************Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!***********************



Senior Manager
Joined: 02 Dec 2014
Posts: 382
Location: Russian Federation
Concentration: General Management, Economics
WE: Sales (Telecommunications)

Re: A train traveled from Station A to Station B at an average speed of 80
[#permalink]
Show Tags
06 Jun 2015, 15:30
EMPOWERgmatRichC wrote: Hi ElCorazon,
The 'goal' to try to answer each Quant question in under 2 minutes is NOT practical. While some questions can be solved relatively quickly (in under 30 seconds), certain questions are designed to take longer to solve (upwards of 3 minutes, and that's if you KNOW what you're doing). These types of "multistep trip" questions are usually wordier, take more steps to solve and require a higher degree of organization and attentiontodetail than most prompts, so it's understandable that you would need MORE than 2 minutes to solve it.
Instead of having a "2 minutes or less" goal, focus more on your overall efficiency  you should try to get this question correct without wasting time.
GMAT assassins aren't born, they're made, Rich Hi Rich! I watched EMPOWERGmat course and you said that if we have a ratios that means that statement is sufficient. Hence answer is D. Do i think logically?=))
_________________
"Are you gangsters?"  "No we are Russians!"



Veritas Prep GMAT Instructor
Joined: 23 Oct 2013
Posts: 144

Re: A train traveled from Station A to Station B at an average speed of 80
[#permalink]
Show Tags
07 Jun 2015, 17:11
This question is not correct, because the statements conflict each other. It is impossible that, given A to B is 80 mph and B to C is 60 mph, both of these statements could be true. Think about this example: Statement 1  assume distance from A to C is 320 miles. Because A to C is 4x B to C, then A to B is 3x B to C. Its a 3:1 ratio in the distances. Therefore we have 240 miles from A to B and 80 miles from B to C. That leaves us with time of 3 hours from A to B and time of 1 hour 20 minutes from B to C. Statement 2 this can't be possible given what we just figured out in statement 1. 3:1.33 does not equal 3:1. The question is flawed.
_________________
Brandon Veritas Prep  GMAT Instructor
If you found this post helpful, please give me kudos!!!
Save $100 on Veritas Prep GMAT Courses And Admissions Consulting Enroll now. Pay later. Take advantage of Veritas Prep's flexible payment plan options.
Veritas Prep Reviews



Math Expert
Joined: 02 Sep 2009
Posts: 47946

Re: A train traveled from Station A to Station B at an average speed of 80
[#permalink]
Show Tags
08 Jun 2015, 03:01
VeritasPrepBrandon wrote: This question is not correct, because the statements conflict each other. It is impossible that, given A to B is 80 mph and B to C is 60 mph, both of these statements could be true. Think about this example:
Statement 1  assume distance from A to C is 320 miles. Because A to C is 4x B to C, then A to B is 3x B to C. Its a 3:1 ratio in the distances. Therefore we have 240 miles from A to B and 80 miles from B to C. That leaves us with time of 3 hours from A to B and time of 1 hour 20 minutes from B to C.
Statement 2 this can't be possible given what we just figured out in statement 1. 3:1.33 does not equal 3:1.
The question is flawed. Thank you for noticing this. Edited the question.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  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



Intern
Joined: 08 May 2018
Posts: 30

Re: A train traveled from Station A to Station B at an average speed of 80
[#permalink]
Show Tags
03 Aug 2018, 01:04
chetan2u wrote: ElCorazon wrote: Is there a quicker way to see that the distance variable cancels out, rather than going through the entire algebraic calculation? I made the assumption that the variable would remain, and struggle to finish in ~ 2 minutes once I start getting into algebra for DS questions. Thanks.. Hi ElCorazon, the Q stem tells us the speed in two different routes and asks us the average speed.. for this we require the distance or the ratio of distances.. lets see the statement.. 1)statement 1 gives us the ratio of distance .. so sufficient.. 2) statement two tells us the ratio of time so multiplying this ratio with speed would give us the ratio of distance .. again sufficient ans D Hello Sir, I have understood the question and the answer to it. However, this question has put questions on my understanding. For "Averages", we take the ratios. I have always understood that when it is average speeds, ratio of "time" needs to be taken and not the ratio of "distances". But here by ratio of distances, we are able to arrive at the average speed. Has my understanding been wrong? Please assist.



Intern
Joined: 06 Jul 2018
Posts: 2

Re: A train traveled from Station A to Station B at an average speed of 80
[#permalink]
Show Tags
04 Aug 2018, 22:25
iam unable to see the options in the question



Math Expert
Joined: 02 Sep 2009
Posts: 47946

Re: A train traveled from Station A to Station B at an average speed of 80
[#permalink]
Show Tags
05 Aug 2018, 04:32
dhanush95 wrote: iam unable to see the options in the question This is a data sufficiency question. Options for DS questions are always the same. The data sufficiency problem consists of a question and two statements, labeled (1) and (2), in which certain data are given. You have to decide whether the data given in the statements are sufficient for answering the question. Using the data given in the statements, plus your knowledge of mathematics and everyday facts (such as the number of days in July or the meaning of the word counterclockwise), you must indicate whether— A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient to answer the question asked. B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient to answer the question asked. C. BOTH statements (1) and (2) TOGETHER are sufficient to answer the question asked, but NEITHER statement ALONE is sufficient to answer the question asked. D. EACH statement ALONE is sufficient to answer the question asked. E. Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data specific to the problem are needed. I suggest you to go through the following posts: ALL YOU NEED FOR QUANT. Ultimate GMAT Quantitative MegathreadHope this helps.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  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




Re: A train traveled from Station A to Station B at an average speed of 80 &nbs
[#permalink]
05 Aug 2018, 04:32






