Respuesta :

Given:
[tex]P(A \cup B)=0.7[/tex]
[tex]P(A \cup B')=0.9[/tex]

Need to find
[tex]P(A)[/tex]

We know that 
[tex]P(A \cup B)+P(A \cup B')=P(A)+P(U)=P(A)+1=1.6[/tex]
=>
[tex]P(A)=1.6-1=0.6[/tex]

This can be illustrated by the attached Venn diagram.
Ver imagen mathmate