400 kg of the seeds containing 30 % by mass of dye, is agitated with 80 m' of solvent for 15 minutes. After cach decanting, 30% of the solution produced remains in the residue. Solvent is saturated with the solute at a concentration of 3 kg/m. Find a. The concentration of the dye in the solution after the leaching and, b. The number of washing such that the concentration of dye in the solid residue is 0.015% by mass. In a pilot scale test using a vessel 1 m in volume, a dye was leached from an seeds and the solvent was 82 % of the saturated in 10 s. Assuming conditions are equivalent to those in the pilot scale vessel