Hi gmat_thingie,
I mentioned this in your other post, but it bears repeating: in a DS prompt, you can't trust any picture you've been given (as far as estimating size or distance is concerned).
Here, we're asked for the Co-ordinates of Point S. From the graph, we know that (0,0) is one co-ordinate on line OS and (5,0) is one co-ordinate on line ST.
Fact 1: The slope of OS = 1/3
Along with the point (0,0), we can now create the equation for line OS:
Y = mX + B
0 = 0/3 + B
B = 0
Line OS is Y = X/3
Unfortunately, this equation has an infinite number of solutions, so we have no way to determine the exact co-ordinate of point S.
Fact 1 is INSUFFICIENT
Fact 2: The slope of ST = 1/2
Along with the point (5,0), we can now create the equation for line ST:
Y = mX + B
0 = 5/2 + B
-2.5 = B
Line ST is Y = X/2 - 2.5
Unfortunately, this equation also has an infinite number of solutions, so we have no way to determine the exact co-ordinate of point S.
Fact 2 is INSUFFICIENT
Combined, we have 2 equations:
Y = X/3
Y = X/2 - 2.5
These 2 equations will criss-cross at just one point: Point S. We COULD determine that co-ordinate, but we don't have to do the math here.
Combined, SUFFICIENT
Final Answer: C
GMAT assassins aren't born, they're made,
Rich
