Oct 20 07:00 AM PDT  09:00 AM PDT Get personalized insights on how to achieve your Target Quant Score. Oct 22 09:00 AM PDT  10:00 AM PDT Watch & learn the Do's and Don’ts for your upcoming interview Oct 22 08:00 PM PDT  09:00 PM PDT On Demand for $79. For a score of 4951 (from current actual score of 40+) AllInOne Standard & 700+ Level Questions (150 questions) Oct 23 08:00 AM PDT  09:00 AM PDT Join an exclusive interview with the people behind the test. If you're taking the GMAT, this is a webinar you cannot afford to miss! Oct 26 07:00 AM PDT  09:00 AM PDT Want to score 90 percentile or higher on GMAT CR? Attend this free webinar to learn how to prethink assumptions and solve the most challenging questions in less than 2 minutes. Oct 27 07:00 AM EDT  09:00 AM PDT Exclusive offer! Get 400+ Practice Questions, 25 Video lessons and 6+ Webinars for FREE. Oct 27 08:00 PM EDT  09:00 PM EDT Strategies and techniques for approaching featured GMAT topics. One hour of live, online instruction
Author 
Message 
TAGS:

Hide Tags

Intern
Joined: 15 Sep 2015
Posts: 8

Train P and Q travel from A to B at 100 mph, and 120 mph respectively.
[#permalink]
Show Tags
01 Dec 2015, 10:42
Question Stats:
66% (02:44) correct 34% (02:52) wrong based on 264 sessions
HideShow timer Statistics
Train P and Q travel from A to B at 100 mph, and 120 mph respectively. Train Q stops for 10 minutes at station C, but reaches Station B, 5 Minutes before Train P. what is the distance between A and B. A) 50 km B) 100 km C) 120 km D) 150 km This is not GMAT Material, so only 4 choices.
So I was going through a couple of varied DRT problems, and this one took longer than it should. My question is, how can I approach it differently? Or more efficiently?
So, what I initially tried do was the following
DRT Px100 t5  Px120 t+10 
100t500 = 120t + 1200
Which is obviously wrong. Then I thought about what I'm actually doing
P's time is five minutes behind T's time after T stops for 10 minutes
P's Time  5 = Q's Time + 10
P's Time = \(\frac{x}{100}\) and Q's Time = \(\frac{x}{120}\)
So we have:
\(\frac{x}{100}\) = \(\frac{x}{120}\) + \(\frac{15}{60}\)
x=150
So, I suppose I was wondering if anyone has any suggestions on tackling these kind of problems? Or maybe a different approach.
Thanks
Official Answer and Stats are available only to registered users. Register/ Login.



CEO
Joined: 20 Mar 2014
Posts: 2596
Concentration: Finance, Strategy
GPA: 3.7
WE: Engineering (Aerospace and Defense)

Re: Train P and Q travel from A to B at 100 mph, and 120 mph respectively.
[#permalink]
Show Tags
01 Dec 2015, 10:55
malkadhi wrote: So I was going through a couple of varied DRT problems, and this one took longer than it should. My question is, how can I approach it differently? Or more efficiently?
Train P and Q travel from A to B at 100 mph, and 120 mph respectively. Train Q stops for 10 minutes at station C, but reaches Station B, 5 Minutes before Train P.
A) 50 km B) 100 km C) 120 km D) 150 km
This is not GMAT Material, so only 4 choices.
So, what I initially tried do was the following
DRT Px100 t5  Px120 t+10 
100t500 = 120t + 1200
Which is obviously wrong. Then I thought about what I'm actually doing
P's time is five minutes behind T's time after T stops for 10 minutes
P's Time  5 = Q's Time + 10
P's Time = \(\frac{x}{100}\) and Q's Time = \(\frac{x}{120}\)
So we have:
\(\frac{x}{100}\) = \(\frac{x}{120}\) + \(\frac{15}{60}\)
x=150
So, I suppose I was wondering if anyone has any suggestions on tackling these kind of problems? Or maybe a different approach.
Thanks Make sure to follow posting guidelines (link in my signatures). All your analyses should either go under "spoilers" or in the next post. This will not dilute the discussion. We do not usually encourage posting of non GMAT questions as this will only develop bad habits. But for a one time discussion, your method is absolutely fine. Realize that the for PS questions in GMAT, you must use the options to your advantage. This is not only provide you the correct option but will also help you in spending lesser time than usual. Time management is of utmost importance GMAT. That being said, once you set up the equation: P's time  5 min = Q's time + 10 minutes > x/100  5/60 = x/120 + 10/60 > x/100x/120 = 15/60 . Now use the values given. Only D will satisfy this.



EMPOWERgmat Instructor
Status: GMAT Assassin/CoFounder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 15294
Location: United States (CA)

Re: Train P and Q travel from A to B at 100 mph, and 120 mph respectively.
[#permalink]
Show Tags
02 Dec 2015, 23:00
Rich malkadhi wrote: Train P and Q travel from A to B at 100 mph, and 120 mph respectively. Train Q stops for 10 minutes at station C, but reaches Station B, 5 Minutes before Train P. what is the distance between A and B.
A) 50 km B) 100 km C) 120 km D) 150 km
Hi malkadhi, What is the source of this question (and does the original source have the typos in it or is it just your transcription)? I ask because the prompt only has 4 answer choices and the answers are in KILOMETERS, while the speeds are in MILES per hour. There are plenty of quality GMAT materials that you can use during your studies, so you might want to stop using this resource. GMAT assassins aren't born, they're made,
_________________
Contact Rich at: Rich.C@empowergmat.comThe Course Used By GMAT Club Moderators To Earn 750+ souvik101990 Score: 760 Q50 V42 ★★★★★ ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★



Senior Manager
Joined: 20 Aug 2015
Posts: 386
Location: India

Re: Train P and Q travel from A to B at 100 mph, and 120 mph respectively.
[#permalink]
Show Tags
07 Dec 2015, 06:46
malkadhi wrote: Train P and Q travel from A to B at 100 mph, and 120 mph respectively. Train Q stops for 10 minutes at station C, but reaches Station B, 5 Minutes before Train P. what is the distance between A and B.
A) 50 km B) 100 km C) 120 km D) 150 km
Since every thing is given in the form of time, let us form an equation in time. Make sure to keep everything in the same unitsAssume the distance between A and B to be x miles. Time taken by Train P = \(\frac{x}{100}\) Time taken by Train Q = \(\frac{x}{120}\) + 10/60 We are given that Train P reaches 5 minutes after Train Q Hence \(\frac{x}{100}\)  5/60 = \(\frac{x}{120}\) + 10/60 \(\frac{x}{100}\)  \(\frac{x}{120}\) = 15/60 \(\frac{6x  5x}{600}\) = 15/60 x = 150 Option D



VP
Joined: 07 Dec 2014
Posts: 1224

Re: Train P and Q travel from A to B at 100 mph, and 120 mph respectively.
[#permalink]
Show Tags
07 Dec 2015, 09:20
t=time of P 100t=120(t1/4) t=3/2 hour (3/2)(100)=150 miles



Senior Manager
Joined: 03 Apr 2013
Posts: 264
Location: India
Concentration: Marketing, Finance
GPA: 3

Re: Train P and Q travel from A to B at 100 mph, and 120 mph respectively.
[#permalink]
Show Tags
28 May 2017, 02:40
malkadhi wrote: Train P and Q travel from A to B at 100 mph, and 120 mph respectively. Train Q stops for 10 minutes at station C, but reaches Station B, 5 Minutes before Train P. what is the distance between A and B. A) 50 km B) 100 km C) 120 km D) 150 km This is not GMAT Material, so only 4 choices.
So I was going through a couple of varied DRT problems, and this one took longer than it should. My question is, how can I approach it differently? Or more efficiently?
So, what I initially tried do was the following
DRT Px100 t5  Px120 t+10 
100t500 = 120t + 1200
Which is obviously wrong. Then I thought about what I'm actually doing
P's time is five minutes behind T's time after T stops for 10 minutes
P's Time  5 = Q's Time + 10
P's Time = \(\frac{x}{100}\) and Q's Time = \(\frac{x}{120}\)
So we have:
\(\frac{x}{100}\) = \(\frac{x}{120}\) + \(\frac{15}{60}\)
x=150
So, I suppose I was wondering if anyone has any suggestions on tackling these kind of problems? Or maybe a different approach.
Thanks Quick way of doing this is by using ratios. Let the number of minutes that it takes P = t minutes. So, for Q it is = t  15 minutes. Ratio of their speeds = 5:6 So, ratio of their times = 6:5 \(\frac{5}{6} = \frac{(t15)}{t}\) t = 90 minutes..or 1.5 hrs.. Thus, distance is \(1.5*100 = 150 km\) (D)
_________________
Spread some love..Like = +1 Kudos



Current Student
Joined: 18 Aug 2016
Posts: 603
Concentration: Strategy, Technology
GMAT 1: 630 Q47 V29 GMAT 2: 740 Q51 V38

Re: Train P and Q travel from A to B at 100 mph, and 120 mph respectively.
[#permalink]
Show Tags
28 May 2017, 02:45
Answer would be 150 Km ..Using options we can reach the answer . P will travel for 15 more mins than Q Sent from my iPhone using GMAT Club Forum
_________________
We must try to achieve the best within us
Thanks Luckisnoexcuse



Manager
Joined: 09 Nov 2015
Posts: 135

Re: Train P and Q travel from A to B at 100 mph, and 120 mph respectively.
[#permalink]
Show Tags
28 May 2017, 08:28
If Q had not stopped for 10 minutes, it would have reached Station B 15 minutes earlier than P. That is, when Q reaches B, P is still 100/4=25 miles behind. Which means that in the time that Q covers the distance AB (lets assume this to be d miles) P covers (d25)miles. Since the ratios of the speeds of the two trains is equal to ratio of the distances covered by them in the same time, we can write: 120/100=d/(d25) Thus, d=150. Answer: D



Intern
Joined: 21 Mar 2012
Posts: 23
Location: India

Re: Train P and Q travel from A to B at 100 mph, and 120 mph respectively.
[#permalink]
Show Tags
28 Jul 2017, 14:49
For Train P S = 100mph D = x miles T = t hrs For Train Q. S= 120mph D = xmiles T = t 1/6 1/12 (Since Train Q stopped for 10 min, i.e. 1/6hrs and reached 5 min earlier, i.e, 1/12 hrs; Therefore total time the Train Q took was t  1/61/12) Distance = Speed * Time 100t = 120 *(t1/61/12) 100t = 120t 2010 20t =30 t= 1.5 hrs Distance = X miles = 100*t = 150 miles malkadhi wrote: Train P and Q travel from A to B at 100 mph, and 120 mph respectively. Train Q stops for 10 minutes at station C, but reaches Station B, 5 Minutes before Train P. what is the distance between A and B. A) 50 km B) 100 km C) 120 km D) 150 km This is not GMAT Material, so only 4 choices.
So I was going through a couple of varied DRT problems, and this one took longer than it should. My question is, how can I approach it differently? Or more efficiently?
So, what I initially tried do was the following
DRT Px100 t5  Px120 t+10 
100t500 = 120t + 1200
Which is obviously wrong. Then I thought about what I'm actually doing
P's time is five minutes behind T's time after T stops for 10 minutes
P's Time  5 = Q's Time + 10
P's Time = \(\frac{x}{100}\) and Q's Time = \(\frac{x}{120}\)
So we have:
\(\frac{x}{100}\) = \(\frac{x}{120}\) + \(\frac{15}{60}\)
x=150
So, I suppose I was wondering if anyone has any suggestions on tackling these kind of problems? Or maybe a different approach.
Thanks



Current Student
Joined: 23 Jul 2015
Posts: 143

Re: Train P and Q travel from A to B at 100 mph, and 120 mph respectively.
[#permalink]
Show Tags
06 Aug 2017, 04:40
Total time taken by Q =\(\frac{D}{120} + \frac{10}{60}\) Total time taken by P =\(\frac{D}{100}\) = Total time take by Q + \(\frac{5}{60}\) \(\frac{D}{120} + \frac{10}{60}\) + \(\frac{1}{12}\) = \(\frac{D}{100}\)
\(\frac{D+30}{120} = \frac{D}{100}\)
Solving for D > D = 150



Director
Joined: 04 Dec 2015
Posts: 743
Location: India
Concentration: Technology, Strategy
Schools: HEC Sept19 intake, ISB '19, Rotman '21, NUS '21, IIMA , IIMB, NTU '20, Bocconi '22, XLRI, Trinity MBA '20, Smurfit "21
WE: Information Technology (Consulting)

Train P and Q travel from A to B at 100 mph, and 120 mph respectively.
[#permalink]
Show Tags
06 Aug 2017, 22:05
malkadhi wrote: Train P and Q travel from A to B at 100 mph, and 120 mph respectively. Train Q stops for 10 minutes at station C, but reaches Station B, 5 Minutes before Train P. what is the distance between A and B.
A) 50 km B) 100 km C) 120 km D) 150 km Let the distance from \(A\) to \(B = D\)
Let the time for Train \(P\) to travel from \(A\) to \(B = t\)
Speed of train \(P = 100\) mph
Distance , \(D = 100*t\)  (i)
Time for Train \(Q\) to travel from \(A\) to \(B = t  (10+5) = t  15\)
Speed of train \(Q = 120\) mph
Distance , \(D = 120 (t15)\)  (ii)
Distance is same for both trains. Therefore equating (i) and (ii) we get;
\(100*t = 120(t15)\)
\(100t = 120t  1800\)
\(20t = 1800\)
\(t = 90\) mins or \(1.5\) hours
Substituting value of '\(t\)' in distance formula, we get;
\(D = 100t = 100 * 1.5\) hours \(= 150\) km
Answer (D)..._________________ Please Press "+1 Kudos" to appreciate.



Senior Manager
Joined: 02 Apr 2014
Posts: 468
Location: India
GPA: 3.5

Re: Train P and Q travel from A to B at 100 mph, and 120 mph respectively.
[#permalink]
Show Tags
01 Jan 2019, 20:33
How do we know both the trains started at same time? This question requires some assumptions




Re: Train P and Q travel from A to B at 100 mph, and 120 mph respectively.
[#permalink]
01 Jan 2019, 20:33






