Let XXX be a continuous random variable with PDF f(x)=3x28f(x) = \frac{3x^2}{8}f(x)=83x2 for 0≤x≤20 \le x \le 20≤x≤2. Find E[X]E[X]E[X].
32\frac{3}{2}23
125\frac{12}{5}512
85\frac{8}{5}58