Solution:
Given the following:
[tex]P(A)+P(B)-P(A\text{ and B\rparen}[/tex]
where
[tex]\begin{gathered} P(A)=\frac{4}{7} \\ P(B)=\frac{3}{7} \\ P(A\text{ and B\rparen=}\frac{2}{7} \end{gathered}[/tex]
By substituting into the above expression, we have
[tex]\begin{gathered} \frac{4}{7}+\frac{3}{7}-\frac{2}{7} \\ =\frac{4+3-2}{7} \\ =\frac{5}{7} \end{gathered}[/tex]
Hence, the answer is
[tex]P(A\text{ or B\rparen}[/tex]
