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

Redeem

Navjit and Leonardo...

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 73
Joined: Tue Sep 09, 2008 11:39 am

Navjit and Leonardo...

by anniev2 » Mon Mar 02, 2009 10:38 am
Please assist me by explaining this answer:

If Navjit and Leonardo each take 6 minutes to walk x yards, how many minutes would it take them to meet each other if they were y yards apart and walked in a straight line toward each other at constant rates?
Attachments
Navjit and Leonardo.jpg
Top
Source: — Problem Solving |
Master | Next Rank: 500 Posts
Posts: 106
Joined: Wed Feb 04, 2009 6:09 am
Location: Louisville, KY
Thanked: 8 times

Re: Navjit and Leonardo...

by marcusking » Mon Mar 02, 2009 12:08 pm
anniev2 wrote:Please assist me by explaining this answer:

If Navjit and Leonardo each take 6 minutes to walk x yards, how many minutes would it take them to meet each other if they were y yards apart and walked in a straight line toward each other at constant rates?
Perhaps the easiest way with this problem is plugging in numbers. Lets just assume x = 6. So if they travel 6 yards at 6 minutes a piece walking towards each other, they will meet in the middle at 3 minutes.

Now lets say y = 12 yards. Since the distance has doubled and the rates of the two people stays the same the time it takes them to meet in the middle should double as well. So we are looking for an equation that will take
x = 6
y = 12
and will give us an answer of 6 minutes

the only one that works it (3y)/x = > (3*12)/6 => 36/6 => 6 the answer we were looking for.
Top
Master | Next Rank: 500 Posts
Posts: 160
Joined: Fri May 30, 2008 7:10 pm
Thanked: 10 times
GMAT Score:600

by dendude » Mon Mar 02, 2009 2:13 pm
This question becomes easy if you use the concept of relative speed.
If two objects are moving in the same direction, the relative speed is the sum of their individual speeds.
If two objects are moving in the opposite direction, the relative speed is the difference between their individual speeds.

I do not want to spend too much of time elaborating on the concept. You can research it online.

In this problem, the relative speed is (x/6) + (x/6) = x/3
Therefore to cover y yards, the time would be
y/(x/3)= 3y/x
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 319
Joined: Wed Feb 04, 2009 10:32 am
Location: Delhi
Thanked: 84 times
Followed by:9 members

by sureshbala » Mon Mar 02, 2009 2:22 pm
Folks, why don't u get into simple logic rather than math and i am sure you will save lot of time in the exam.

Individually they can cover x mts in 6 minutes, which means
Together (from opposite ends) they can cover x mts in 3 minutes.

So to cover y mts together, time taken = y/x *3
Choice E
Top
Post new topic Post Reply
• Page 1 of 1