Three unbiased coins are tossed together. What is the probability of getting at most two heads?

Difficulty: Easy

Correct Answer: 7/8

Explanation:

Given data

  • Number of coins = 3; each fair (unbiased).

Concept/ApproachAt most two heads = 1 − P(three heads).

Step-by-Step calculation Total outcomes = 23 = 8 P(3 heads) = 1 ÷ 8 P(at most 2 heads) = 1 − 1÷8 = 7÷8

Verification/AlternativeDirect sum: P(0H) + P(1H) + P(2H) = 1÷8 + 3÷8 + 3÷8 = 7÷8.

Final Answer7/8

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