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GATE 2018 ME (ME2) – Question 10

General Aptitude · Quantitative Aptitude: Arithmetic and Number Computation · 2 marks · Multiple choice

An unbiased coin is tossed six times per trial. Four trials give (1) HTHTHT, (2) TTHHHT, (3) HTTHHT, (4) HHHT__ __, where H is head and T tail. Which statement about the last two tosses has the highest probability?

  1. Two T will occur.
  2. One H and one T will occur.
  3. Two H will occur.
  4. One H will be followed by one T.

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Show answer and explanation

Correct answer: (B) One H and one T will occur.

Explanation

Independent fair tosses give HH,HT,TH,TT, each probability 1/4, regardless of previous observations. One head and one tail includes HT or TH, probability 1/2, while a specified order has only 1/4. Hence **B** is most probable.