A jar contains 30 red marbles, 50 blue marbles, and 20 white marbles. You choose one marble from the jar at random. What is the theoretical probability of choosing a white marble?
The probability of choosing a white marble can be calculated by dividing the number of white marbles by the total number of marbles in the jar.
Number of white marbles = 20
Total number of marbles = 30 (red) + 50 (blue) + 20 (white) = 100
Therefore, the probability of choosing a white marble is 20/100 = 1/5 = 0.2 = 20%.