A ventilating system is to be installed in a building. It will require 400 hours of work to install it. Each workman takes a total of 1/2-hour to get out his tools in the morning and put them away at night. He also takes a total of 1/4-hour to get to his workplace and back again each day. He is also given a 1/4-hour break in the morning and another in the afternoon. If 5 men are in the work crew, how many hours of work are done each day?