Multiple choice

A coin is tossed 4 times. What is the probability of getting at least 2 heads?

  1. 6/8

  2. 11/16

  3. 5/8

  4. None of these

  5. 1/8
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B Correct answer
Explanation

Total outcomes = 2^4 = 16. Outcomes with 0 heads = 1 (TTTT). Outcomes with 1 head = 4 (HTTT, THTT, TTHT, TTTH). Outcomes with at least 2 heads = 16 - (1 + 4) = 11. Probability = 11/16.

AI explanation

Using the binomial probability formula, the probability of getting exactly k heads in n tosses is given by (n C k) times (1/2)^n. The probability of getting at least two heads is the sum of the probabilities of getting exactly 2, 3, and 4 heads, which is (4 C 2 + 4 C 3 + 4 C 4) divided by 2^4. This evaluates to (6 + 4 + 1) divided by 16, which equals 11/16. The result is 11/16.

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