A jar contains 30 red marbles, 50 blue marbles, and 20 white marbles. you pick one marble from the jar at random. find the theoretical probability.

First, find the sum of all the marbles that you have. That is 100 in total.

The probability of you getting a blue marble is 50/100, or 1/2, or 50%

A red marble is 30/100, or 3/10, or 30%

White 20/100, 1/5, 20%