Let XXX have CDF F(x)=x38F(x) = \frac{x^3}{8}F(x)=8x3 for 0≤x≤20 \le x \le 20≤x≤2. What is P(X∈(0.5,1.5))P(X \in (0.5, 1.5))P(X∈(0.5,1.5))?
78\frac{7}{8}87
1964\frac{19}{64}6419
18\frac{1}{8}81
2764\frac{27}{64}6427