Dainty Donuts has been experiencing record sales this year 2014. Eagerly, Vanessa Vasquez, owner and CEO, plans to move the Head Office from her home at U.P. Village, Diliman, Quezon City to the 10th floor of Magastos Building at Ortigas Center, Pasig City. In preparation for the upgrade, she is working on the layout of the 150-sqm floor of her new Head Office. She has the following options:

The floor can be divided into four, five, or six parts. One part will be Vanessa Vazquez's office. Another part will be a conference room, donut-shaped, of course.

Each of the remaining parts can contain six, seven, or eight office workers.

a. How many floor layouts are possible?

b. Excluding the CEO, what is the range (i.e. minimum and maximum number) of office workers that all the possible floor layouts can accommodate?

c. Assume that Vasquez has decided to divide the floor into four parts. What is the average number of workers that the floor layout can accommodate? Exclude Vasquez from your count.