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TS EAMCET · Maths · Probability

A bag contains \(2 n+1\) coins. It is known that \(n\) of these coins have a head on both sides, whereas the remaining \(n+1\) coins are fair. A coin is picked up at random from the bag and tossed. If the probability that the toss results in a head is \(\frac{31}{42}\), then \(n\) is equal to

  1. A \(10\)
  2. B \(11\)
  3. C \(12\)
  4. D \(13\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(10\)

Step-by-step Solution

Detailed explanation

The probability that the toss results is a tail \(=\frac{(n+1)}{2(2 n+1)}\) \(\therefore 1-\frac{(n+1)}{2(2 n+1)}\) is the probability that the toss result is a head.…