A.qANAqBNB/(NA +NB)!B.qANA·qBNBC.qANA/N!·qBNB/NB!D.(qA·qB)NA +NB
A.306KB.443KC.760KD.556K
A.2.2×104B.2.0×104C.2.0×103D.2.2×105