A storage tank is still 1% empty after 50 liters of petrol have been filled into it. How many additional liters (rounded to two decimal places) of petrol will be needed to completely fill the tank?

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?