Probability Calculator
Compute P(A or B), P(neither) for independent events A and B.
Input Data
P A
P B
Results
P(A or B).
0.15
Chance at least one occurs.
0.65
Chance neither occurs.
0.35
Explanatory note about the result.
皆發生=15.00%；至少一=65.00%；皆不=35.00%
At a glance:For independent A, B: P(A or B) = pA+pB−pA·pB; P(neither) = (1−pA)(1−pB). Complements coin-flip and combination.
Formula
P(A or B) = pA + pB − pA·pB.
P(neither) = (1−pA)(1−pB).
How to Use
- Enter pA and pB.
- The tool returns either/neither.
Case Studies
pA=0.5, pB=0.3
either = 0.65; neither = 0.35.
FAQ
Independent required?
Yes — the formula assumes A and B do not influence each other.
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References
Content review: Calculatorism Math Team. Results are for reference only; please refer to the relevant authorities for the official figures.