Answer
There exists a person who has a large income and is not happy.
Work Step by Step
Recall the definition of sufficient:
"$\forall x$, r(x) is a sufficient condition for s(x)" means "$\forall x$, if r(x) then s(x)."
In this case r(x) is: person has a large income.
s(x) is: person is happy.
Recall the form of the negation of a universal conditional statement:
$~(\forall x, P(x) \rightarrow Q(x)) \equiv \exists x$ such that $(P(x) \land $ ~$Q(x))$
In this case, the negation is: $\exists$ x, such that r(x) and ~s(x), which is: "there exists a person who has a large income and is not happy."
