Multiple choice

Three unbiased cins are tossed. What is the probability of getting atmost two heads?

  1. $\dfrac{3}{ 4}$
  2. $\dfrac{1} {4}$
  3. $\dfrac{3}{8}$
  4. $\dfrac{7}{8}$
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D Correct answer
Explanation

Total outcomes for 3 coins = 2^3 = 8. Outcomes with 3 heads = 1 (HHH). Outcomes with at most 2 heads = Total - 3 heads = 8 - 1 = 7. Probability = 7/8.

AI explanation

The probability of getting at most two heads is found by subtracting the probability of getting exactly three heads from 1. When three unbiased coins are tossed, the total number of outcomes is 2^3, which is 8. There is only 1 outcome with exactly three heads, so the probability of three heads is 1/8, and subtracting this from 1 gives 1 minus 1/8, which is 7/8.

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