David tunes pianos in his spare time for extra income. Buyers of his service are willing to pay $135 per tuning. One particular week, David is willing to tune the first piano for $115, the second piano for $125, the third piano for $140, and the fourth piano for $175. Assume David is rational in deciding how many pianos to tune. His producer surplus is __.

Assume that (i) setups need to be completed first; (ii) a setup can only start once the batch has arrived at the resource, and (iii) all flow units of a batch need to be processed at a resource before any of the units of the batch can be moved to the next resource. process step 1 molding 2 painting 3 dressing setup time 15 min. 30 min. no setup processing time 0.25 min./unit 0.15 min./unit 0.30 min./unit which batch size would minimize inventory without decreasing the process capacity?