P(event) = frequency of event ÷ total number of events
A complimentary event is the opposite of P(event) = 1 - P(event)
a) P(blue) = 4/(4+1+2) = 4/7
b) P(green) = 1/7
c) P(not green) = 1 - P(green) = 1 - 6/7
d) P(not purple) = 1 or 100%, since there ARE no purple marbles in the bag
e) P(red) = 2/7