A pulse of radioactive Ba-140 was injected into a 10-in. pipeline (25.5 cm ID) 293 km long used for pumping petroleum products (u = 81.7 cm/s, Re = 2400) from Rangely, Colorado to Salt Lake City, Utah. Estimate the time of passage of fluid having more than 1/2 C_max from Rangely, Colorado to Salt Lake City, Utah. Estimate the time of passage of fluid having more than C > C_max/2 occurs between θ̈ + 118 σ_θ. This may be helpful information. Data from Hull and Kent, Ind. Eng. Chem., 44,2745 (1952).