4/15 of the employees walk to work.
Total fraction of employees: We know that the sum of the fractions for driving, traveling by bus, and walking must equal 1, representing all employees.
Fraction driving and taking the bus: We are given that 2/5 of employees drive to work and 1/3 travel by bus. So, the combined fraction for these two modes of transportation is 2/5 + 1/3 = 11/15.
Fraction walking: Since the remaining employees must walk, the fraction of employees who walk is 1 - 11/15 = 4/15.