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GATE 2025 ME – Question 14

Engineering Mathematics · Probability and Statistics: Probability, conditional probability, sampling theorems · 1 mark · Multiple choice

If two unbiased coins are tossed, then what is the probability of having at least one head?

  1. 0.25
  2. 0.5
  3. 0.675
  4. 0.75

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Correct answer: (D) 0.75

Explanation

The only outcome with no head is tails on both coins, which has probability $\frac{1}{4}$. So the probability of at least one head is $1 - \frac{1}{4} = 0.75$.