GRE Big Book Test 17 Section 3 Q3

A little confused about the process for solving this problem, I thought it was D because the values can range from (19 - x) to (19 + x) and (18 - x) to (18 + x) for the two distances. I thought there would some shared values for the distance and some values that would not be shared for the distances between the towns. Thank you!

Anwser is B?

I think you dismissed the part where it says “only roads”.

You’re looking at a completely new road, which doesn’t exist in the diagram

Well I think it’s B because distance can’t be -ve.

Even if for some reason x were allowed to be negative, the answer would still not be D.

We are comparing 18 + x and 19 + x; it should be evident that 19 + x is always greater for all real values of x.

What is x ?

x is distance from coaltown to seburg.

although distance can never be -ve, as you said let’s say x is -ve integer.

Let x = -3

Now put the value of x inside the equation

19+x

19+(-3)

19-3

So this is clearly wrong.

So we can’t assume x -ve in any scenario because distance is either 0 or greater than 0.