Algebra
posted by #@@# .
A bag contain 9 red, 8 yellow, 5 pink and 6 blue marbles. The experiment is to randomly select on marble out of the bag. What is the probability that chosen marble is a)blue? b)yellow? c) red or pink d)green or blue? need to know what all are

Use common sense.
For each color, to get the probability of that color, divide the number of marbles with that color by the sum of all marbles (28).
for example:
P(blue) = 6/28 = 3/14