Let XXX and YYY have joint PDF f(x,y)=12xy(1−x)f(x, y) = 12xy(1-x)f(x,y)=12xy(1−x) for 0≤x≤1,0≤y≤10 \le x \le 1, 0 \le y \le 10≤x≤1,0≤y≤1. What is E[Y]E[Y]E[Y]?
1/2
1/3
2/3
1/4