gmat sets DS II

[clammiestqasar]

In the xy-plane, what is the slope of line l?
(1) Line l dose not intersect the line with equation y = 1 - x.
(2) Line l intersects the line with equation y = x - 1.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.

[Makushr1]

In the xy-plane, what is the slope of line l?
(1) Line l dose not intersect the line with equation y = 1 - x.
(2) Line l intersects the line with equation y = x - 1.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.

Answer is A.

1) The only way for a line to never intersect with another line is it they are parallel.
2) no idea what the slope is, other than it's not y=x-1

[clammiestqasar]

how can the ans be A if we cannot determine the slope from the given information?

[Makushr1]

how can the ans be A if we cannot determine the slope from the given information?

If 2 lines on a plane never intersect, they are parallel. So, since A states the line doesn't intersect with another line with the equation y=1-x, line L's equation must also be y=1-x

[von]

What's the OA?

[clammiestqasar]

WHy cant the equation be something else?THey are parallel lines and not identical lines?

[gmatmachoman]

how can the ans be A if we cannot determine the slope from the given information?

If 2 lines on a plane never intersect, they are parallel. So, since A states the line doesn't intersect with another line with the equation y=1-x, line L's equation must also be y=1-x

For parallel lines : m1 = m2

having said that, its not necessary that intercepts are going to be the same:

L1 : y = 3x +3

L2 ; y = 3x + 5

L3: Y = 3x +15

All L1,L2,L3 are parallel , means they wont intersect. They have same slope ( 3) in the above example.

A is sufficient as we can identify the slope.

[Makushr1]

WHy cant the equation be something else?THey are parallel lines and not identical lines?

They don't have the same intercept, but that itsn't the question. The question is asking if the SLOPE is the same. If 2 lines never intersect on a plane, they must be parallel. Parallel lines have the same slope.

[missrochelle]

i think the key point missing here is that if there are 2 lines in an xy plane, they either intersect or are parallel. those are the only two options. if they dont intersect, then they are parallel and have the same slope.

[missrochelle]

i think the key point missing here is that if there are 2 lines in an xy plane, they either intersect or are parallel. those are the only two options. if they dont intersect, then they are parallel and have the same slope.