In a market survey, 20% opted for Product A, 60% opted for Product B, while the remaining people were uncertain. If the difference between those who opted for Product B and those who were uncertain was 720, how many people were covered in the survey?

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?