GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video
close
It is currently 05 Mar 2021, 08:49
Register
GMAT Club Tests
Decision Tracker
My Rewards
New posts
New comers' posts

Close

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
Your Progress

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.

Go to My Error Log Learn more
Close

Request Expert Reply

Confirm Cancel
The amount of coal a train burns each mile is directly propo
7 posts Go to First Unread Post
Print view
NEW TOPIC
POST REPLY
Downloads
My Bookmarks
Reviews
SORT BY:
Date
Kudos
Tags:
Find Similar Topics 

Show Tags
Hide Tags

avatar
gmatmathguy123
Intern
Intern
Joined: 04 May 2010
Posts: 1
The amount of coal a train burns each mile is directly propo [#permalink] New post  Updated on: 26 May 2014, 01:11
1
Kudos
11
Bookmarks
00:00
A
B
C
D
E

Difficulty:

15% (low)

Question Stats:

75% (01:24) correct 25% (01:26) wrong based on 433 sessions

Hide Show timer Statistics

The amount of coal a train burns each mile is directly proportional to the speed at which it travels. How much coal will it burn on this particular 60 mile trip?

(1) On a previous trip, the train burned 100 pounds of coal on a 60 mile trip at 60 miles per hour
(2) On this particular trip, the train is travelling at a speed of 30 miles per hour.


Show Spoiler
(isn't the second statement irrelevant? because once you know the value of the constant of fuel burned per speed (directly proportional to one another so it doesnt change in value), you know the distance, and since rate and time are inversely proportional to one another, doesn't the actual rate become unimportant? The book answer to this question was C, but I don't understand why its not A...)
ShowHide Answer
Official Answer
Official Answer and Stats are available only to registered users. Register/Login.

Originally posted by gmatmathguy123 on 04 May 2010, 05:13.
Last edited by Bunuel on 26 May 2014, 01:11, edited 2 times in total.
OA added
avatar
nverma
Manager
Manager
Joined: 24 Jul 2009
Posts: 170
Re: DS question... [#permalink] New post  04 May 2010, 06:29
1
Kudos
gmatmathguy123 wrote:
The amount of coal a train burns each mile is directly proportional to the speed at which it travels. How much coal will it burn on this particular 60 mile trip?
(1) On a previous trip, the train burned 100 pounds of coal on a 60 mile trip at 60 mph
(2) On this particular trip, the train is traveling at a speed of 30mph



(isn't the second statement irrelevant? because once you know the value of the constant of fuel burned per speed (directly proportional to one another so it doesnt change in value), you know the distance, and since rate and time are inversely proportional to one another, doesn't the actual rate become unimportant? The book answer to this question was C, but I don't understand why its not A...)


Given C = k*M, where C is amount of coal/per mile, k proportionality constant, and M speed of the train.
So, We have to find C and distance is given as 60
To find C, we need the value of k and the speed at which present journey is made.

Statement 1:
(100/60) = k*(60).. So k is 1/36, (Old journey..!!)
Now we have k..
DO we know the value of speed during the present journey..NO. INSUFFICIENT

Statement 2:
C = k* (60/30)
We have the speed of the present journey. But don't have the value of K.INSUFFICIENT

Statement 2 and Statement 1:
For present journey, we have K and the speed.. Answer C.
avatar
dixitraghav
Manager
Manager
Joined: 16 Feb 2010
Posts: 91
Re: DS question... [#permalink] New post  16 May 2010, 11:51
since the amount of coal the train burns is directly proportional to speed so the train burns a diffrent total amount of coal on the journey, more speed more amout of coal would be burnt, to get the fixed amount there must be a fixed speed which is provided by statement B , hence C is the right answer.
avatar
subratam99
Intern
Intern
Joined: 21 Mar 2010
Posts: 12
GMAT ToolKit User
Re: DS question... [#permalink] New post  17 May 2010, 21:31
The amount of coal a train burns each mile is directly proportional to the speed at which it travels. How much coal will it burn on this particular 60 mile trip?
(1) On a previous trip, the train burned 100 pounds of coal on a 60 mile trip at 60 mph
(2) On this particular trip, the train is traveling at a speed of 30mph


We must know the speed of the train on this particular 60 mile trip. Second statement provides speed of 30mph.
Furthermore, We must know the constant associated with the proportion. Obviously, first statement helps to find the constant.
Therefore, We need both of the statements to answer the question.
Hence, answer is C
avatar
Sindbad
Intern
Intern
Joined: 11 Aug 2013
Posts: 23
Location: India
Concentration: Finance, General Management
GMAT 1: 620 Q47 V28
GPA: 3.23
WE:Information Technology (Investment Banking)
Re: The amount of coal a train burns each mile is directly propo [#permalink] New post  03 Jun 2014, 08:24
To answer the question we require to know the value of 2 parameters
1. Speed of the train
2. Rate of consumption of the coal.

From Option(1) we can only get rate of consumption of the coal. Speed of the train is unknown. Hence INSUFFICIENT
From Option(2) We only have the speed of the train. rate of consumption of coal is Unkown. Again INSUFFICIENT

Combining (1) and(2) we clearly get both the parameters

Hope This Helps
avatar
ashutosh4018
Intern
Intern
Joined: 05 Jun 2016
Posts: 1
Re: The amount of coal a train burns each mile is directly propo [#permalink] New post  17 Jul 2016, 23:32
Sindbad wrote:
To answer the question we require to know the value of 2 parameters
1. Speed of the train
2. Rate of consumption of the coal.

From Option(1) we can only get rate of consumption of the coal. Speed of the train is unknown. Hence INSUFFICIENT
From Option(2) We only have the speed of the train. rate of consumption of coal is Unkown. Again INSUFFICIENT

Combining (1) and(2) we clearly get both the parameters

Hope This Helps

People implied here that => if y is proportional to x, it means y = mx .
But its actually y = mx +c . Here is the special case since if speed is 0, we are taking special condition and saying fuel consumed will be 0.
If it was anything other than speed and coal consumption question, i think that time answer should have been E.
But i am not sure of that also.. :( Can anyone please confirm it ??
avatar
G
basshead
VP
VP
Joined: 09 Jan 2020
Posts: 1162
Premium Member
Re: The amount of coal a train burns each mile is directly propo [#permalink] New post  13 Oct 2020, 09:52
No calculation is needed for this question. We are told the amount of coal a train burns each mile is directly proportional to the speed at which it travels. So we will need to know the speed of the train.

(1) Tells us the amount of coal burned for a given speed. However, we do not know the speed of the train for this particular trip. Insufficient.
(2) Gives us the speed of the train. However, we do not know the proportion of coal/per mile burned. Insufficient.

(1 & 2) We have the proportionality constant and the speed of the train. Sufficient.
_________________
Help me get better -- please critique my responses!
Signature Read More
GMAT Club Bot
gmatclubot
[#permalink]
NEW TOPIC
POST REPLY
Downloads
My Bookmarks
Reviews
Moderators:
chetan2u
Math Expert
9525 posts
Bunuel
Math Expert
72430 posts
GMATBusters
Retired Moderator
1979 posts
nick1816
DS Forum Moderator
2245 posts
Feedback

cron

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Main navigation

GMAT Resources

Partners

MBA Resources

www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions