There are 8 faces with even numbers. (2, 4, ..., 16)
There are 5 odd primes between 1 and 16. (3, 5, 7, 11, 13)
There is no common element between the two lists, so the events are disjoint. Therefore
[tex]\mathbb P(\text{even OR odd prime})=\mathbb P(\text{even})+\mathbb P(\text{odd prime})=\dfrac8{16}+\dfrac5{16}=\dfrac{13}{16}\approx0.813[/tex]
