we know that
5 character options and 4 weapons options
so
Total outcomes =5*4=20
step 1
Not be an ef
P=16/20
step 2
use an axe
P=5/20 ------> (include 4/20 of the previous probabilty)
so
The probability is equal to
(16/20)+(5/20)-(4/20)=17/20
The answer is 17/20