Re: New Set of Mixed Questions!!!
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01 Apr 2013, 14:46
Q2.
lets consider the 4 cases for x and y:
for x>0, y>0
x/3 + y/3 = 10 => 3x + y = 90 (valid for x and y > 0)
for x>0, y<0
x/3 - y/3 = 10 => 3x - y = 90 (valid for x > 0 and y < 0)
for x<0, y<0
-x/3 - y/3 = 10 => -3x - y = 90 (valid for x and y < 0)
for x<0, y>0
-x/3 + y/3 = 10 => -3x + y = 90 (valid for x and y >0)
if we plot these 4 graphs the region enclosed is a rhombus with the 4 vertices being: (30,0); (0,90), (-30,0) and (0,-90)
One of the diagonals is 60 units long and the other diagonal is 180 units long.
area of this enclosed space = (diag 1 * diag 2)/2 => (60 * 180)/2
=5400
hence D