Multiple choice

There unbiased coins are tossed. What is the probability of getting atmost $2$ heads?

  1. $\dfrac34$
  2. $\dfrac14$

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  3. $\dfrac38$
  4. $\dfrac78$
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D Correct answer
Explanation

With three unbiased coins, there are 8 equally likely outcomes. At most 2 heads excludes only the outcome with 3 heads, so the probability is 7/8.

AI explanation

When three unbiased coins are tossed, the total number of possible outcomes is 2 cubed, which equals 8. The probability of getting at most 2 heads is found by subtracting the probability of getting exactly 3 heads from 1. The only outcome with 3 heads is HHH, so its probability is 1 divided by 8. Therefore, the required probability is 1 minus 1 divided by 8, which equals 7 divided by 8.

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