You have ten shipments of diesel engines, each shipment contains 500 or more engines. The manufacturer just sent you a bulletin that one of the shipments is made of engines that are missing a hard to locate internal component, and would like you to ship it back, at their expense. Unfortunately all the manifests indicate the correct weights.
Your large scale is a little finicky and can only be trusted for the first measurement of the day [so you only get one shot at it]
The missing component has a mass of 5kg, and the normal diesel engine has a mass of 1,000kg. The scale has a capacity of 75,000kg and an ability to detect a difference of 2.5kg.
What is your plan to correctly identify the defective shipment in one measurement of the scale with the minimal cost of moving the engines to the scale by forklift? You may assume all the engines in a shipment have 0 variance in weights within their lot