aalekhoza wrote:
DavidTutorexamPALHey David, Thanks for your reply.
A drawing indeed explains things well, so here is my exact questions for you in a drawing format. I mean to ask why are the angles not the sum of all
green angles? Why are we taking the
red angles to count the total sum of the degrees by which the man has turned? Please see image attached.
Thanks
Hey
aalekhoza,
Going back to the original question's drawing, I think you may be right -- the question could be referring to the 'green angles' only.
Even if it is, however, you still need to know that the park is a polygon* to know that the degree-sum is 360 (and if you don't count turns in the opposite direction as having 'negative' degrees, then you need to know that it is a convex polygon). Note that the original question does not state that the park is a polygon, though the drawing makes us want to think that it is.
The shape of the park is not given in the question stem or in stmt (1), but is given in (2), which tells us that it is a (convex) quadrilateral. Therefore (2) is sufficient and (B) is the answer.
*Technically speaking, if the exterior of the park is a closed curve which doesn't cross itself, and if you measure degrees with respect to a specific orientation (i.e. if turning 'left' is 'positive' then turning' 'right' is 'negative'), then their sum is always 360. Look up 'winding number' on Wikpedia if you like, but keep in mind that this is well above anything GMAT-related.
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