2020年9月21日 · The probability of having 6 boys first and then 1 girl is 0.0078125. There is only one possible combination that can work, which is BBBBBBG. S = {BBBBBBG, BBBBBGB, BBBBGBB, BBBGBBB, BBGBBBB, BGBBBBB, GBBBBBB} S is the sample space with possible combinations of 6 boys and 1 girl in any order. P(6 boys and 1 girl) = 7/128 = 0.0546875