Two hours after X leaves college, Y leaves his home

very nice question. Although simple, question attacks the understanding and thus a gmat style.

We don't know X's route so cant comment on where and when they will meet.

Until now I have never come across a quant question in RTD that adopts such an approach ( almost similar to assumption question type in CR!)

Two hours after X leaves college, Y leaves his home to intercept him. If Y travels twice as fast as X, how long will it take Y to meet X?

Speed Y = 2x

(1) X's college is 50 miles due north of Y’s home

There are two problems here. a.) I wouldn't put it past the GMAT to trick us by saying the distance between x and home is 50 miles but the route traveled is longer than 50 miles. b.) Though we know that Y travels twice as fast as X, we don't know what speed Y travels at. For example, X may travel at 1 mile/hour and Y may travel at 2 miles/hour or X may travel at 10 miles/hour and Y at 20 miles/hour. Obviously, depending on the rate they travel at, the time it takes them to meet will vary.
INSUFFICIENT

(2) Y’s rate is 30 mph

This tells us Y's rate (and X's as well, given the information in the stem) but we know nothing about the distance they both travel.
INSUFFICIENT

1+2)

I think the "due north" bit should raise some red flags in people's mind. This is an uncommon way to refer to distance in any real application. For example, when I refer to the distance from NYC to Boston (a route I travel often) I don't mean the distance they are from one another in a straight line, but rather the distance they are from one another by the road way or in my case, the train tracks. Straight line distance is meaningless unless you're taking a helicopter or plane, something I doubt comes into play with X and Y!

That being said, unless we know the actual distance they traveled, we cannot solve for this problem.
INSUFFICIENT

(E)

Thing is we don't know towards what direction is X walking. If X is walking towards Y's home it will be different as if X is walking away from Y's home.
We don't have this info in any of the statements

So clear E for me

Hope it helps
Cheers!
J

I think the answer should be B as we have speed and time. Distance is irrelevant here.
If x's speed is v then y's speed will be 2v
In order to meet, A and B have to travel the same distance
v(t) = 2v(t-2)
t=4

Why would you Assume that they should travel the same distance to meet? They can meet at any point in that 50 mile distance.

A)
I rather propose that the combined total distance they travel when they meet has to be 50 (this too assuming the distance travelled is a straight line by both of them and few other things). So the equation becomes:

vt + 2v(t-2) = 50

3vt - 4v = 50 -> This CAN'T be solved further. Hence data insufficient.

B)

Supplies v in the above equation - so you can then arrive at the value of t. Techinally, gives you the answer.


BUT, this is with the assumption that they both are following the same exact straight line route - the words "Intercept" and "due north" is making me very comfortable with this assumption!! Hence, even after I combine both the information given - data is Insufficient.



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