In the xy-plane, a triangle has vertices (0,0), (4,0) and (4,8). If a point (a,b) is selected at random from the triangular region, What is the probability that a-b>0? Choose the correct choice:
A) 1/5  B) 1/3  C) 1/2  D) 2/3  E) 4/5
The area of the right triangle is (1/2)*4*8= 
<gadget id="calculator">(1/2)*4*8</gadget>
<output>16</output>
16.   Only the points (a,b) below the line y=x satisfy a - b &gt; 0.   The part of the triangle which is below the line y=x has an area of (1/2)(4)(4) = 8.   P(a - b &gt; 0) = 8/16 = 1/2   The answer is 1/2.
<result>C</result>
In the xy-plane, a triangle has vertices (0,0), (4,0) and (4,8). If a point (a,b) is selected at random from the triangular region, What is the probability that a-b>0?