In a city in which there are 90,000 employed workers, 18,000 are public employees. Of this number, 6,000 are employed by the federal government, 8,000 by the state, and 4,000 by the city.

a. What percent of all workers are public employees?

b. What percent of the public employees are employed by the federal government?

c. What percent of all employees are employees of the state?