What is the value of w in terms of x and y?

Hi All,

For anyone who finds this question 'complex-looking', you can solve it rather easily by TESTing VALUES. There are a few math rules that you have to follow though:

1) The angles in a line sum to 180 degrees
2) The angles in a triangle sum to 180 degrees

Try TESTing a VALUE for X and Y, then fill in all of the various angles in this picture.....You'll end up with a value for W and a way to see if the various answers match.

GMAT assassins aren't born, they're made,
Rich

MAGOOSH OFFICIAL SOLUTION:
Here's the same diagram with letters. First of all, look at the big triangle, triangle ACE. We know the three angles in this or any triangle must add up to 180°. Let's say that ∠E = k. Then we know

x + y + k = 180, or k = 180 – x – y

Now, look at the angles around point F. Those three angles form a straight line, that is to say, a 180° angle, so the sum of the three angles there must also be 180°. Since one is x and one is y, the other has to be k --- ∠DFE = k

Now, look at triangle DEF. The sum of the three angles in this triangle must also be 180°.

w + k + k = 180°

w = 180 – 2k

Now, we have an expression for w in terms of k. To express w in terms of x & y, we need to substitute the expression for k above, k = 180 – x – y

w = 180 – 2(180 – x – y)

w = 180 – 360 + 2x + 2y

w = 2x + 2y – 180

Answer = (A)

Here
w+x+y = 180 degree -----------------------------1
so <x = 180 degree - x -y
and <y = 180 degree - x -y
then put the value of angle x and y in equation 1
w+ 180 degree - x -y +180 degree - x -y = 180 degree
w+360 degree - 2x-2y = 180 degree
w = 2x + 2y -360 degree +180 degree
w = 2x+2y -180
The result abjectly matches with A

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