A Random Variable X Has a Density Function F(x) = $\frac { 24 } { x ^ { 3 } }$

Short Answer

A random variable X has a density function f(x) = $\frac { 24 } { x ^ { 3 } }$ , 3 ≤ x ≤ 6. Find b such that $\operatorname { Pr } ( X \leq b ) = 0.4$ .
Enter your answer exactly in the reduced form a $\sqrt { \frac { b } { c } }$ , unlabeled.