Let XXX and YYY have joint PDF f(x,y)=1f(x, y) = 1f(x,y)=1 for 0≤x≤1,0≤y≤10 \le x \le 1, 0 \le y \le 10≤x≤1,0≤y≤1. What is P(X+Y≥1.5)P(X+Y \ge 1.5)P(X+Y≥1.5)?
1/81/81/8
1/41/41/4
1/21/21/2
3/83/83/8