Scaling a vegetable preparation with trimming loss

A Korean catering kitchen has a tested vegetable recipe yielding forty portions. Each portion requires eighty grams of usable prepared vegetable. The next event requires one hundred and twenty portions, and the purchase specification gives an expected preparation yield of eighty percent. The quoted raw ingredient price is three thousand won per kilogram. The manager asks for a purchase estimate and ingredient cost, while another worker proposes buying only the final usable weight. Sufficient refrigerator and preparation capacity is available, but the kitchen will still use its documented production and holding controls. All quantities and prices are explicit assumptions for this exercise; they are not official examination specifications or legal food-storage limits.