Brain Teasers & Mental Math
A coin is biased with P(heads) = 0.7. You flip it 3 times. What is the probability of getting exactly one head?
Model answer
C(3,1) × 0.7¹ × 0.3² = 3 × 0.7 × 0.09 = 0.189 ≈ 18.9%. For biased coins you…
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