Answer
unsuccessful new authors
unsuccessful or new authors
15
75
Work Step by Step
$N\cap U$ is the set of unsuccessful new authors.
$N\cup U$ is the set of unsuccessful or new authors.
As we can see it from the table, $n(N\cap U)=15$
$n(N\cup U)=n(N)+n(U)-n(N\cap U)=20+70-15=75$
