`(+)-`Butan`-2-ol` has `[alpha]_(D)^(20) =+13.9^(@)`.a sample of butane`2-ol` contianing both the enantiomers was found to have a specific rotation value of `-3.5^(@)` under similar conditions. The percentages of the `(+)` and `(-)` enantiomers present in the mixture are, respectively,