Gmat_mission wrote: ↑Thu Nov 19, 2020 11:29 am
2020-04-28_1909.png
In the figure shown, is \(l_1\parallel l_2?\)
(1) \(r = s\)
(2) \(t = u\)
Answer:
E
Source: Official Guide
Target question: In the figure shown, is [m]l_1||l_2[/m] ?
When I SCAN the two statements, I can see that statement 1 tells me about 2 angles created by the intersection of
line_1 and line m
And statement 2 tells me about 2 angles created by the intersection of
line_2 and line m
Since none of the information relates
line_1 and
line_2, I’m pretty sure I can identify some cases with conflicting answers to the
target question.
So, I’m going to head straight to……
Statements 1 and 2 combined
Key concept: For ANY 2 intersecting lines, the opposite angles will ALWAYS be equal
There are several scenarios that satisfy BOTH statements. Here are two:
Case a:
In this case, the answer to the target question is
YES, of the two lines ARE parallel
Case b:
In this case, the answer to the target question is
NO, of the two lines are NOT parallel
Since we cannot answer the
target question with certainty, the combined statements are NOT SUFFICIENT
Answer: E
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
