Problem Solving (PS) | In the xy-plane, a triangle ABC consists of 3 points A(0,0), B(6,0),

Hi,

attached is how I approached it, and got 1/2 instead of 1/3.
General approach seems to be correct, but I am thinking that the area of smaller triangle shoul be 18, not 12, because the question asks for situation where Y (= height) is less than X (=base), so I drew a triangle (shaded area), where base = 6, height =6.

Where am I wrong with this?? Please enlighten me!!Bunuel

Thank you so much in advance!