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JEE Main201910 Apr 2019Morning ShiftMathematicsProbabilityActual

Assume that each born child is equally likely to be a boy or girl. If two families have two children each, then the conditional probability that all children are girls given that at least two are girls is:

Options

  1. A1 12
  2. B1 10
  3. C1 11
  4. D1 17

Correct answer

C. 1 11

Step-by-step solution

Family has four children in total. ∴ Total number of ways in which at least two girls are there is 4 C 2 + 4 C 3 + 4 C 4 = 11 Favourable case in which all are girls is = 1 ∴   P = 1 11

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