Management of the factory in problem 4 is considering replacement of the wet cleaning technology by a dry clean technology. Dry clean machines costing $125,000 each process one wafer at a time. For any cleaning step performed using dry clean machines, the Takt time per lot is 125 minutes and the standard cycle time per lot is 127 minutes. Availability of the dry clean machines is estimated to be 96%, with MTTR = 3 hours and TTR = 3.5 hours. In the process flow for the main product of this factory, there are 20 wet cleaning steps using recipe A, 10 steps using recipe B, and 20 steps using recipe C. Each of the 50 steps would be replaced by a dry clean step. Assume arrival rates of 25-wafer lots at cleaning steps would remain the same as in question 4. (a) (8 points) How many dry clean machines would need to be purchased such that the total ECT for cleaning the main product does not exceed the total ECT currently required for the wet clean steps performed on the main product? (b) (4 points) Management does not understand ECT analysis and decides to replace the two wet clean stations