$\left\{ \begin{matrix}P(A)=P(B)=x  \\P(A\bigcap B)=P(A).P(B)={{x}^{2}}  \\\end{matrix} \right.$ $P(A\bigcup B)=P(A)+P(B)-P(A\bigcap B)$ $=2x-{{x}^{2}}=0/64\Rightarrow \left\{ \begin{matrix}x=1/6  \\x=0/4  \\\end{matrix} \right.$ $\Rightarrow P(A)=P(B)=0/4\,\,,\,\,P(A\bigcap B)=0/16$ $P(A-B)=P(A)-P(A\bigcap B)=0/4-0/16=0/24$