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Find the probability of a simple event

Probability of a simple event is the ratio of favorable outcomes to the total number of equally likely outcomes in a clearly defined sample space, expressed as a fraction, decimal, or percent between 0 and 1. The value describes the event’s likelihood, with 0 representing impossibility and 1 certainty; this understanding supports proportional reasoning and later work with compound events, while conditional probability and dependent, multi-stage situations are not included here.

Detailed Explanation: Find the probability of a simple event

A simple event is one outcome or group of outcomes you are interested in, such as picking a red marble.

To find its probability:

Probability=number of favorable outcomestotal number of equally likely outcomes\text{Probability}=\frac{\text{number of favorable outcomes}}{\text{total number of equally likely outcomes}}

Example: A bag contains 33 red marbles and 22 blue marbles. What is the probability of choosing a red marble?

  1. Count all possible outcomes.
    There are (3+2=5)(3+2=5) marbles in the bag, so the total number of outcomes is 55.

  2. Count the favorable outcomes.
    The favorable outcomes are the 33 red marbles.

  3. Write the probability as a fraction.

P(red)=35 P(\text{red})=\frac{3}{5}

  1. Convert if needed.

35=0.6=60% \frac{3}{5}=0.6=60\%

So, the probability of choosing a red marble is 35\boxed{\frac{3}{5}}, or (0.6)(0.6), or (60%)(60\%). A probability is always between 00 and 11: 00 means impossible, and 11 means certain.

Learn by doing: Find the probability of a simple event

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    Probability - Coins (1), All Specific, To Fraction

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