Probability = # of desired results / # of total results
We want the probability that a marble is not purple. There are 16 marbles total which are not purple. There are 25 total marbles.
P(not purple) = # of not purple / # of total marbles
P(not purple) = 16 / 25
P(not purple) = 0.64 = 64%
Answer: 64%
Hope this helps!