| Multiplication Rule: When two events, A and B, are dependent, the probability of both occurring is: P(A and B)= P(A)xP(B|A) |
Example- A math teacher gave her class two tests. 25% of the class passed both tests and 42% of the class passed the first test. What percent of those who passed the first test also passed the second test?
 |  | Start with Multiplication Rule 2. |
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 | | Divide both sides of equation by P(A). |
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 | | Cancel P(A)s on right-hand side of equation. |
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 | | Commute the equation. |
 | | We have derived the formula for conditional probability. |
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