Answer
$n(P'\cup N)=80$
This value represents the number of non-pharmaceutical stocks or unchanged stocks, or both.
Work Step by Step
$n(S)=100,~~n(P)=50,~~N(n)=40$
$n(P')=n(S)-n(P)=100-50=50$
$n(P'\cap N)=n(E \cap N)+n(I \cap N)=0+10=10$
$n(P'\cup N)=n(P')+n(N)-n(P'\cap N)=50+40-10=80$
This value represents the number of non-pharmaceutical stocks or unchanged stocks, or both.