In an examination, 40% of the students failed in Mathematics and 30% failed in English. It is also known that 18% of the students failed in both Mathematics and English. If the number of students who passed both subjects is 540, find the total number of students in the examination.

In a town with 30,000 professionals, teachers make up 11% of the total professionals. If 46% of teachers are male, what is the number of female teachers in the town?

In a town's professional breakdown, doctors represent 18% and clerks represent 8% of the total professionals. If the number of doctors is 3000 greater than the number of clerks, what is the total number of professionals in the town?