Substances A and B have retention times of 16.40 and 17.63 min, respectively, on a 30.0-cm column. An unretained species passes through the column in 1.30 min. The peak widths (at base) for A and B are 1.11 and 1.21 min, respectively. (d) the length of column required to achieve a resolution of 1.5, (e) the time required to elute substance B on the column that gives an Rs value of 1.5 (f) the plate height required for a resolution of 1.5 on the original 30-cm column and in the original time