The enthalpies of neutralisation of a string acid `HA` and a weaker acid `HB` by `NaOH` are `-13.7` and `-12.7 kcal Eq^(-1)`, respectively. When one equivalent of `NaOH` is added to a mixture containing one equivalent of `HA` and `HB`, the enthalpy change was `-13.5kcal`. In what ratio is the base distributed between `HA` and `HB`?