Multiple choice

If n coins are tossed then find the probability of not getting either all heads or all tails

  1. $\displaystyle 1-\frac{1}{2^{n}}$
  2. $\displaystyle \frac{1}{2^{n-1}}$
  3. $\displaystyle 1-\frac{1}{2^{n+1}}$
  4. $\displaystyle 1-\frac{1}{2^{n-1}}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Total outcomes = 2^n. Outcomes with all heads = 1. Outcomes with all tails = 1. Probability of (all heads or all tails) = 2 / 2^n = 1 / 2^(n-1). Probability of NOT getting these = 1 - 1 / 2^(n-1).

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