In the xy-plane, a triangle has vertices (0,0), (4,0) and (4,7). 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 from the following choices.
A) 4/7 B) 2/3 C) 3/5 D) 3/7 E) 1/2
The area of the right triangle is (1/2)*4*7= 
<gadget id="calculator">(1/2)*4*7</gadget>
<output>14</output>
14.   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) = 8/14 = 4/7   The answer is 4/7.
<result>A</result>
In the xy-plane, a triangle has vertices (0,0), (4,0) and (4,7). If a point (a,b) is selected at random from the triangular region, What is the probability that a-b>0?