Events & Promotions
|
|
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Apr 2601:30 AM EDT
-02:30 AM EDT
Learn how Keshav, a Chartered Accountant, scored an impressive 705 on GMAT in just 30 days with GMATWhiz's expert guidance. In this video, he shares preparation tips and strategies that worked for him, including the mock, time management, and more.
Apr 2610:00 AM EDT
-11:00 AM EDT
The Target Test Prep course represents a quantum leap forward in GMAT preparation, a radical reinterpretation of the way that students should study. Try before you buy with a 5-day, full-access trial of the course for FREE!
Apr 2512:30 AM EDT
-01:30 AM EDT
At one point, she believed GMAT wasn’t for her. After scoring 595, self-doubt crept in and she questioned her potential. But instead of quitting, she made the right strategic changes. The result? A remarkable comeback to 695. Check out how Saakshi did it.
Apr 2711:00 AM EDT
-12:00 PM EDT
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors
Apr 2808:00 AM PDT
-11:00 AM PDT
Whether you are just beginning your MBA journey or fine-tuning your path to a 700+ score, GMAT Day is designed to give you a competitive edge.
May 0111:00 AM PDT
-12:00 PM PDT
Free- full-length test + 15 concept videos + 150+ short videos + study plan!
Updated on: 25 Oct 2013, 09:16
Originally posted by rvinodhini on 21 Dec 2011, 06:33.
Last edited by Bunuel on 25 Oct 2013, 09:16, edited 1 time in total.
Last edited by Bunuel on 25 Oct 2013, 09:16, edited 1 time in total.
RENAMED THE TOPIC.
Kudos
Bookmarks
A man travels 120 miles by ship, 450 by train and 60 by car taking altogether 13 hours and 30 minutes for the entire journey. The speed of the train is 3 times that of the car and 1.5 times that of the ship. Find the speed of the train.
speed of car = x miles/hr
speed of ship=2x miles/hr
speed of train = 3x miles/hr
soln 1:
Total distance travelled=120+450+60=630 miles
Total time = 13.5 or 27/2 hours
Total speed = 6x miles per hour
hence 6x *27/2 = 630
x= 70/9
hence speed of train (3x)=70/3 or 23.3
Soln 2 :
Time taken by the train = distance/speed = 450/3x or 150/x
ship=120/2x or 60/x
car =60/x
since the total time ix 27/2 we can equate them
150/x+60/x+60/x=27/2
270/x=27/2 ---> x = 20
hence speed of train (3x) = 60 m/hr
why am i getting 2 different solns ? which method is wrong and why ..
speed of car = x miles/hr
speed of ship=2x miles/hr
speed of train = 3x miles/hr
soln 1:
Total distance travelled=120+450+60=630 miles
Total time = 13.5 or 27/2 hours
Total speed = 6x miles per hour
hence 6x *27/2 = 630
x= 70/9
hence speed of train (3x)=70/3 or 23.3
Soln 2 :
Time taken by the train = distance/speed = 450/3x or 150/x
ship=120/2x or 60/x
car =60/x
since the total time ix 27/2 we can equate them
150/x+60/x+60/x=27/2
270/x=27/2 ---> x = 20
hence speed of train (3x) = 60 m/hr
why am i getting 2 different solns ? which method is wrong and why ..
21 Dec 2011, 07:14
Kudos
Bookmarks
rvinodhini
The first solution is the one that's incorrect. I highlighted the mistake in red. You just added the three speeds to find what you've called the 'total speed', and then used it as if it were the average speed. You do not add speeds together to find average speed - for example, If you travel, say, 20 mph by car, then 60 mph by train, your average speed will never be 80 mph. It will be somewhere between 20 and 60 mph.
21 Dec 2011, 07:23
Kudos
Bookmarks
Quote:
Oops ..I get it know ... Thanks Stewart
lesson learnt ...NEVER ADD SPEEDS...
