Facility Layout - production - operations

You're trying to lay out your t-shirt business office. There are 3 rooms in a row (room 1 | room 2 | room 3) wtih 1 door in between room 1 and 2 and 1 door between room 2 and 3. You need to fit your three functions into the rooms -- administration, bleaching, and coloring. You go between administration and branding 30 times a day, you go between administration and cutting 50 times a day, and you go between branding and cutting 100 times a day. If you lay out your functions in a way that minimize the total number of doors you need to open, how many doors do you open each day?