BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Question - Speed, Time & Distance

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Fri Feb 26, 2016 2:07 pm
renanmenezes wrote:A high-speed train takes x hours to cover z km that separate city A from city B. A conventional train takes y hours to cover the same distance. If the high-speed train leaves the city A towards B and conventional train leaves from B toward A at the same time, how many kilometers the high speed train will have traveled over conventional train when they pass each other?
When you post a problem, please include the answer choices.
I posted a solution to this problem here:
https://www.beatthegmat.com/distance-of- ... tml#766111
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Top
User avatar
Legendary Member
Posts: 2135
Joined: Mon Feb 03, 2014 9:26 am
Location: https://martymurraycoaching.com/
Thanked: 955 times
Followed by:140 members
GMAT Score:800

by MartyMurray » Fri Feb 26, 2016 2:21 pm
It takes the high-speed train x hours to travel the z miles from Town A to Town B at a constant rate, while it takes the regular train y hours to travel the same distance at a constant rate. If the high-speed train leaves Town A for Town B at the same time that the regular train leaves Town B for Town A, how many more miles will the high-speed train have traveled than the regular train when the two trains pass each other?

(A) z(y - x) / (x + y)
(B) z(x - y) / (x + y)
(C) z(x + y) / (y - x)
(D) xy(x - y) / (x + y)
(E) xy(y - x) / (x + y)
Rate = Distance/Time

The rate of the high speed train is z/x

The rate of the conventional train is z/y.

Time = Distance/Rate

The time the trains travel to meet each other is Distance/Combined Rates = z/[(z/x) + (z/y)].

Distance = Rate * Time

During that time, the high speed train will go distance z/x * z/[(z/x) + (z/y)].

The conventional train will go distance z/y * z/[(z/x) + (z/y)].

So the difference between the distances the two trains will have gone will be the following.

(z/x - z/y) * z/[(z/x) + (z/y)]

Simplify.

z(y - x) / (x + y)

The correct answer is A.
Marty Murray
Perfect Scoring Tutor With Over a Decade of Experience
MartyMurrayCoaching.com
Contact me at [email protected] for a free consultation.
Top
Post new topic Post Reply
• Page 1 of 1