In the xy-plane, a triangle has vertices (0,0), (4,0) and (4,10). If a point (a,b) is selected at random from the triangular region, What is the probability that a-b>0?
Choose the correct option
A) 1/5	B) 1/3	C) 1/2	D) 2/3	E) 2/5
The area of the right triangle is (1/2)*4*10= 
<gadget id="calculator">(1/2)*4*10</gadget>
<output>20</output>
20.   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) = 8/20 = 2/5   The answer is 2/5.
<result>E</result>
In the xy-plane, a triangle has vertices (0,0), (4,0) and (4,10). If a point (a,b) is selected at random from the triangular region, What is the probability that a-b>0?