... means the wastage rate is: 100/40,000=0.25% . Error of changing paper:Human calculating usually estimate by experience, normally ... change paper 30 times: 30*20/40,000=1.5% . Error of changing order:Because human can not control the rotary ... , if each day change order 50 times, each time the error is 5 M, the wastage rate: 50*5/ 40,000 ...