Note that two intersecting lines make 4 angles around the point of intersection such that vertically opposite angles are equal. Can one of the angles be 320 degrees? The other needs to be 320 degrees too. If a is 320, c needs to be 320 too!





Hence, the options (C), (D) and (E) are not possible.

Now it is just about looking for a pair of supplementary angles.
If x = 10, 2x + 16x = 18x = 180
So 2x = 20 degrees and the angle supplementary to 16x would be 20 degrees too making these two lines parallel.

Answer (B)

Is question asking for the minimum value of x?

No basically we need to figure out WHEN x has a certain value to have lines parallel

The minimum value is x=10 but the question is different when asking



Hope this helps

Lets try with x and 2x ---> x +2x = 180 for line to be ||-----> 3x = 180 ---> x = 60, so options 10, 15, 20 are okay, with 10 being the 1st in the queue to satisfy the condition.

Ans is option B

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