A Hotel Stocks White, Cream and Blue Pillowcases

A hotel stocks white, cream and blue pillowcases. Currently they have 400 white, 120 cream and 80 blue pillowcases. What is the probability of picking a blue pillowcase at random (3 decimal places) ?

A) 0.133
B) 0.150
C) 0.185
D) 0.222