a couple decides to have 6 children . if they succeed in having 6 children and each child is equally likely to be a boy or a girl , what is the probability that they will have exactly 3 girls and 3 boys ?
"sample space = 2 ^ 6 = 64 . favourable events = { bbbggg } , { bgbgbg } , { bgbggb } , { bggbbg } { gggbbb } , { gbgbgb } , { gbbggb } . { gbgbbg } { gbbgbg } probability = 9 / 64 = 9 / 64 ans ( b ) ."
subtract(3, multiply(divide(factorial(6), factorial(3)), power(divide(3, 3), 6)))