Consider a separation performed on a 35. 0 mm long open tubular colum with a 0. 500 mm diameter and a 2. 0 μ m thick stationary phase. Compound a eluted at 12. 63 min and compund b eluted at 13. 30 min. A compund known not to be retained at all by the stationary phase eluted at 1. 145 min. Calculate the relative retention.