if a, b, and c are three numbers on the number line shown

[dw6586]

<-----a------b----->

if a, b, and c are three numbers on the number line shown above, is c between a and b?

(1) b < 0
(2) a - b > c


Ans e

i don't understand why (2) is not sufficient, given the number line shown. it looks from the number line that a < b.

but in the explanation, they give examples such that a = 0 and b = -2. i'm baffled ... am i supposed to assume that even when they list something out on a number line, the order may not actually be shown correctly? (i understand some figures may not be drawn accurately, but i assumed the order of numbers on a number line wouldn't fall in this case??)

[tim]

if this is a gmat prep question, there shouldn't be an "explanation". can you post a screen shot of the question and solution?

[dw6586]

here is a screenshot of the problem.

http://s10.postimage.org/53yzizu0p/Scre ... _54_PM.png

[tim]

i stand corrected. glad to see they include explanations now. looks like a typo here, and i'm not really sure what they meant to do so i can't "fix" their problem..

[ghong14]

I can see why statement 1 and 2 by themselves are not sufficient. However, I have not been able to make a scenario to prove both statements together are insufficient. Care to make an explanation please? Thanks in advance!

[tim]

Try (-4,-2,-3) and (-4,-2,-5) for (a,b,c)

Here's how you could come up with examples on your own:

pick a negative number for b
pick a number less than that for a
for c, pick a number that is less than a-b and that is also between a and b (for a yes), and then pick a number less than a (for a no)