For a continuous random variable XXX with PDF f(x)=13f(x) = \frac{1}{3}f(x)=31 for x∈[0,3]x \in [0, 3]x∈[0,3], find P(X≤1)P(X \leq 1)P(X≤1).
1/3
1/2
2/3
1