How to Do Probabilities in Math
- 1). List the total number of possible outcomes. For example, if you have a bag containing three red marbles, four blue ones, five green ones and six black ones, add the marbles to get the total. Probability in this case involves pulling a ball without any bias; that means the marble is pulled out blindly. In this example, the addition yields 18.
- 2). Jot down the likelihood of a single possibility taking place. For example, determine that since there are four blue marbles, there are four chances of you drawing a blue marble from the bag. Similarly, for the black marbles, they number six within the bag.
- 3). Divide the chance of drawing one marble from the bag bearing the marbles. For instance, the chance or probability of drawing a green marble is 5/18. In the same way, probability of drawing a red marble is 3/18, drawing a blue one is 4/18 and drawing a black one is 6/18. Reduce the probabilities to the simplest form where possible. For example, 4/18 simplifies to "two to nine" and 6/18 simplifies to "one to three."
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