Combined Probability Problems

Many probability problems combine several rules at once. Two especially useful combined results for independent events A and B are:

• P(A and B) = P(A) × P(B) — the AND rule
• P(at least one of A or B) = 1 − P(neither) — the complement of “neither happens”

Solve multi-step problems combining the AND rule and the at-least-one rule.

Continue exploring related topics:

• Addition Rule of Probability
• Independent Events - When One Does Not Affect the Other
• Expected Value - The Long-Run Average Outcome