question_answer

If \[\frac{1}{p}-\frac{1}{q}-\frac{1}{r}=\frac{1}{18}\] and \[pq\text{ }+\text{ }qr\text{ }=\text{ }pr\]then find the value of r.

A) 0                                 

B) 1           

C) 18                                

D) -36

E) None of these