Since ABCD is a square, it is clear that AB=6.
Therefore, if EB= 6-2b then AE= 2b.
AE is the base of the shaded triangle.
If the probability of a randomly selected point lying in the shaded triangle is 1/3. This will equal the (Area of the shaded triangle/ area of the square).
The area of the square ABDE is 6^2= 36.
Determined by 1/3= Area of triangle/ 36. This will give the area of the triangle to be 12.
The area of the triangle = (2b*2b)/2, which is 2b^2=12.
b^2=6 and therefore the value of b= √6 > 2.
Giving us the the answer A
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