30・18 Two prime numbers $p, q$ are exactly the roots of the integer coefficient equation $x^{2}-99 x+m=0$, then the value of $\frac{p}{q}+\frac{q}{p}$ is
(A) 9413.
(B) $\frac{9413}{194}$.
(C) $\frac{9413}{99}$.
(D) $\frac{9413}{97}$.
(E) None of the above answers is correct.
(China Beijing Junior High School Mathematics Competition, 1983)
[Solution] The two primes $p, q$ are the roots of the integer coefficient equation $x^{2}-99 x+m=0$. Therefore, $p+q=99$. It is easy to see that $p, q$ are 2 and 97, respectively. Then
$$
\frac{p}{q}+\frac{q}{p}=\frac{97}{2}+\frac{2}{97}=\frac{9413}{194} .
$$

Therefore, the answer is $(B)$.