If a real number x is chosen at random in the interval [0,3] and a real number y is chosen at random in the interval [0,5], what is the probability that x < y?  Choices
A) 23/30 B) 7/12 C) 11/15 D) 7/10 E) 3/4
Since x is in [0,3] and y is in [0,5] we can draw a rectangle in the coordinate plane with vertices (0, 0), (3, 0), (0, 5), and (3, 5).   The points above the line y=x satisfy x &lt; y.   The part of the rectangle below y=x has an area of 4.5.   The whole rectangle has an area of 15.   P(x &lt; y) = (15-4.5)/15 = 21/30 = 7/10   The answer is 7/10.
<result>D</result>
If a real number x is chosen at random in the interval [0,3] and a real number y is chosen at random in the interval [0,5], what is the probability that x < y?