A park is divided into 8 sections of cedar trees and 3 sections of pine trees. Each section of cedar trees contains 7 trees 15 feet or taller and 5 trees shorter than 15 feet. Each section of pine trees contains 12 trees 15 feet or taller and 9 trees shorter than 15 feet. If one tree is selected at random from the combined sections, what is the probability that it is a pine tree, given it is 15 feet or taller?