Question

In one avenue there are seven healthy trees and five trees affected by a certain disease
in the following order in a row S HHH SS HHHH SS (s for sick , h for healthy) How likely is
it at purely coincidental arrangement of seven healthy and five sick trees that they (like
above) in a maximum of three groups of sick trees and a maximum of two groups of healthy
trees ( group means here at least one tree) are divided?

Answer 1