Let X,YX, YX,Y be independent Uniform(0,1) random variables. What is P(X+Y≤1.5)P(X + Y \le 1.5)P(X+Y≤1.5)?
34\frac{3}{4}43
1516\frac{15}{16}1615
78\frac{7}{8}87
12\frac{1}{2}21