Respuesta :

Recall the inclusion/exclusion principle:

[tex]\mathbb P(Q\cup R)=\mathbb P(Q)+\mathbb P(R)-\mathbb P(Q\cap R)[/tex]

which means

[tex]\mathbb P(Q\text{ or }R)=\dfrac35+\dfrac13-\dfrac15=\dfrac{11}{15}[/tex]