A machine manufactures spare parts at the rate of 20,000per month. A second machine uses those spare parts at the rate of 50,000 per month and the remainder is put into stock. it costs 100,000 to set up the machine, the company establish their stock hold cost 20% per annum of the average stock value. each parts cost 250 to make. what batch size should be produced on the first machine and at what frequency?