Navjit and Leonardo...

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.

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

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