Probability of x = Every probability is a fraction. The largest a probability can be is 1; a probability of 1 indicates total
certainty. The smallest a probability can be is 0, meaning that it’s something that cannot happen.
Furthermore, you can find the probability that something WILL NOT happen by subtracting the probability
that it WILL happen from 1. For example, if the weatherman tells you that there is a 0.3 probability of rain
today, then there must be a 0.7 probability that it won’t rain, because 1 – 0.3 = 0.7. Figuring out the
probability of any single event is usually simple. When you flip a coin, there are only two possible
outcomes, heads and tails; the probability of getting heads is therefore 1 out of 2, or . When you roll a
die, there are six possible outcomes, 1 through 6; the odds of getting a 6 is therefore . The odds of
getting an even result when rolling a die are because there are 3 even results in 6 possible outcomes.
Here’s an example of a probability question:
2.A bag contains 7 blue marbles and 14 marbles that are not blue. If one marble is drawn
at random from the bag, what is the probability that the marble is blue?A)B)
C)
D)
Here’s How to Crack It
Here, there are 21 marbles in the bag, 7 of which are blue. The probability that a marble chosen at
random would be blue is therefore , or . The correct answer is (A).
Some probability questions might include variables. Not to worry. Plugging in will save the day!