To solve for the intersection probability, substitute the classical probabilities (favorable outcomes divided by total outcomes) into the inclusion-exclusion formula, keep a common denominator during the algebraic steps, and isolate the unknown intersection term.
Conditions: The sample space is finite and all outcomes are equally likely.; The probabilities of the two individual events and their union are known.
To solve for the intersection probability, substitute the classical probabilities (favorable outcomes divided by total outcomes) into the inclusion-exclusion formula, keep a common denominator during the algebraic steps, and isolate the unknown intersection term.
Conditions: The sample space is finite and all outcomes are equally likely.; The probabilities of the two individual events and their union are known.