why cu remain unchanged (100) when another opportunity exists for selling the goods(50$). $10 contributed to Co so why $50 didn't apply to Cu based on remaining units that will be sold at reduced price
to find cumulative probability you add all the probabilities before it, i.e., At D=4, Prob.=0.1; At D=5, Prob.=0.2; Therefore at this point, the CUmulative Prob.=0.1+0.2=0.3
