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An unbiased coin is tossed eight times. The probability of obtaining at least one head and at least one tail is:

Options

  1. A127 128
  2. B63 64
  3. C255 256
  4. D1 2

Correct answer

A. 127 128

Step-by-step solution

Probability of at least one head and at least one tail can be calculated as, =   1 - P A l l   H e a d + P A l l   T a i l = 1 - 1 2 8 + 1 2 8 = 1 - 1 2 7 = 1 - 1 128 = 127 128

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