|PF| =  = 9.

|CF| = 18 + 9 = 27.


Hint (instruction).

1. In any triangle, medians are concurrent, i.e. three medians have the common intersection.

2. The common intersection point divides each median in proportion 2:1 counting from the corresponding vertex. 

Regarding these properties, see the lesson Medians of a triangle are concurrent in this site.