The expected value \(E(x)=2.25\) for this probability function. Find \(p\) and \(q\).

\[\begin{array}{ | c | c | c | c | c |}\hline x & 1 & 2 & 3 & 4 \\ \hline P(X=x) & p & 0.15 & 0.25 & q \\ \hline \end{array}\]