The straight-line distance between Town A and Town B is 15 km. Most

chetan2u bb did you hear anything from GMAC on this? I got this in FE4 and spend good 3.5 minutes to find correct answer by using Pythagoras but the option choice didn't give correct answer.

Just got this question in the FE mock 4 as the first question after an intense quant section. Spent almost 5 min 10 seconds on it. Just waste of time. I was so confused.

I’m sending this question to GMAC today.

Guys, I keep seeing all comments with people saying they spent a ton of time on this question. I hope you came back to it later because GMAT has ability to come back and change the answer and I hope you didn’t just spend five minutes of your time on the question that was wrong to start with. Because I don’t know where you’re getting those five minutes. I couldn’t afford more than two really or three at most. so I hope you use this as a lesson that no question is worth five minutes unless of course you got an amazing score and in that case you should be sharing some of your strategies, which is always welcome.

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Without a value of 12 in column 2, the question is plainly wrong - there isn't a single pair that would match the facts given in the question.

The most likely possibility is a simple typo error, in which the number "13" should have actually been "12".

The only other (unlikely) possibility I can think of is to try approximation. Of course, I do recognize that this is EXTREMELY unlikely, because the question clearly states "values of x and y that are jointly consistent with the given information"

But let's say for a moment that we try to find a pair of x and y (such that x>y) to give us the nearest answer to 15 for the hypotenuse. In that case, we would have got x = 8 and y = 13, giving us the hypotenuse as 15.26.

But even in this unlikely scenario, the answers do not match the answers shown by GMAC.

gmac thinks this statement is clear enough to suggest that the first highway is perpendicular to the second.

they may need to think again.

IMO, I don't think there's any ambiguity on that aspect - isn't west always perpendicular to north? Or am I missing some scenario where west is NOT perpendicular to north?

Yes. I agree, if we are only talking about two directions.

Traveling west and then north, presented in the prompt, is different. The two highways could be perpendicular to each other but not must be, because we are not living on a chess board formed by some vertical and horizontal lines.
When we talk about heading north in real life, do we really mean to move towards the North Pole with no deviation?

Will you reply to the forum if/when you get a response? I think it’s really unfair that we paid for and spent so much time on a mock exam that had an incorrect question in it… that was the first question I got wrong on the paper and it completely changed the difficulty level for the rest of my questions, rendering my final score completely inaccurate and useless…

Yes, we ARE in fact living on a giant (curved) chessboard with (imaginary) vertical (longitude) and horizontal (latitude) lines on it.

So by definition, even in real life, north always means towards the north pole. If you deviate, then you can't say you're heading north any more! The amount of deviation is quantified by the angle between your actual (deviated) direction and north.

A slight deviation from north could be north-north-east (22.5 degrees deviation), a bigger deviation from north could be north-east (45 degrees deviation), an even bigger deviation from north could be east (90 degrees deviation), and the maximum possible deviation from north would be south (180 degrees deviation).

The point is, none of those deviations can be called north.­

In GMAT, any position would be given in exact directions. West and north will be perpendicular.

If you are going west on a highway, in actuals you will almost always NOT travel in a straight line. But here west means west and a straight line.

­I have the same thought with the others. However if GMAC confirm that the answer choices have no error, then the only explanation I can think of is the wording of North and West.

Notice that we can still make a triangle using c < a+b rule, for the majority of pairs in the choices, yet if we visualize them, they will have a shape which make them not pointing West when moving in the direction of the first Highway.

If we take a straight line from A to the intersection with the other pairs, it might as well direct us to North West (45 degree from town A)

Hence, even though it is not a perfect right triangle, the deviation from 13 - 9 pair is only minimum that it will still be relevant to say we go west then north to reach Town B.

Maybe...

Does anyone know how to solve this? I am so confused

The solutions are given above. Go through them and ask if any query

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Never heard back 😢
Will try again to remind and check on it again

it is not given anywhere that it is a right angle triangle all we know is x>y and straight line distance between A and B is 15 which is the shortest possible distance between two points(being the straight line) now by pythagorean theorem we know for a fact that x^2 + y^2 >= 225.
has it been a right angle triangle 12 an 9 would be the only option but here in this question, not necessarily.

so 13 and 9 makes sense. It should be the correct answer.

chetan2u please correct me if my reasoning is flawed.­

­No, that may not be logical nad related.

Furter even 8^2 + 13^2 > 15^2, or 9^2+13^2 >15^2 or 10^2+13^2 >15^2.
So how do you come down to possibility of only 9^2+13^2

They have still not fixed it! I got the question on Mock 4 yesterday with a 13 instead of 12