How do I solve 4.3(a) to get the answer? please help

4.3 A rectangular horizontal flow sedimentation tank is designed to treat 1,800 m/day of wastewater. The tank aims to remove suspended solids of density 2,800 kg/m with an overflow velocity limited to 24 m/m2.day and weir loading of 100 m/m-day. The density of the wastewater is 1,000 kg/m3 and its viscosity is 0.001 Pa.s. (a) If the length to width ratio for the tank is 4:1, determine the dimensions of the tank. (3 marks) 4.3(a) L = 17.3 m, W = 4.3 m