10: A supplier to Toyota stamps out parts using a press. Changing a part type requires the supplier to change the die on the press. This changeover currently takes four hours. The supplier estimates that each hour spent on the changeover costs $500. Demand for parts is 1,000 per month. Each part costs the supplier $200, and the supplier incurs an annual holding cost of 25%. a. Determine the optimal production batch size for the supplier. b. Toyota wants the supplier to reduce its batch size by a factor of 2; that is, if the supplier currently produces Q parts per batch, Toyota would like them to produce Q/2 parts per batch. What should the supplier do in order to make this amount optimal for him? (In other words, what setup time creates a scenario in which the optimal batch size drops to 1/2 of its current level?)