Probability of an event
Probability of an event is a number that shows how likely that event is to happen.
Practice This ConceptMain explanation
Teacher explanation
When all outcomes are equally likely, probability is found by dividing favourable outcomes by total outcomes. A bigger value means a greater chance of happening, while 0 means impossible and 1 means certain. In school problems, the sample space must be complete before you calculate probability.
Example
If a bag has 3 red balls and 2 blue balls, the probability of drawing a red ball is 3/5.
Simple analogy
Favourable over total, not favourable over favourable.
Common confusion
Students sometimes divide by the number of favourable outcomes instead of the total number of outcomes.
Exam tip
First write the sample space or total number of outcomes, then count only the favourable ones.
Answer writing and exam use
1-mark use
Write the exact meaning of probability of an event in one clean line.
2-mark use
Define probability of an event and add one example or condition.
3-mark use
Explain probability of an event, show the method or example, and mention the common mistake.
Practice this concept with focused MCQs
Open the concept quiz intro first, review the test details, and then start a focused MCQ set from this concept only. Instant score and answer review are live now.
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