MathRevolution
Is x+y<180?
1) Line a and line b are NOT parallel
2) r+q>180
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Statement 1
Line a and line b are NOT parallel
If line a and b had been parallel then x + y would have been 180
Since it is given that a and b are not parallel, there are two possible situations as seen in the attached image.
Attachment:
Solution.png [ 10.94 KiB | Viewed 3068 times ]
Situation 1: lines a and b are converging towards each other as we move from left to right
In this situation x + y will always be less than 180. (Note:
r + q > 180)
Situation 2: lines a and b are moving away from each other as we move from left to right
In this situation x + y will always be greater than 180. (Note: r + q < 180)
So, statement 1 is insufficient
Statement 2
r+q>180
If r + q had been equal to 180, then a and b would have been parallel.
As
r+q>180, a and b are not parallel.
So we could have had the same 2 situations as in statement 1 above.
But we know that
r+q>180 and this is only possible in situation 1 , i.e.lines a and b converge towards each other as we move from left to right.
In this situation, x + y will always be less than 180
Hence, this statement is sufficient.
Answer - B
Moderator Note: Attached the image