Suppose you have ordinal response, for example letter grades y {"A","B","C","D","F"} and x is hours per week studying.

Suppose x and y follow a cumulative logit model.

a)If p[y="A" or "B"|x=4]=0.4, p[y="A" or "B"|x=5]=0.5, what isp[y="A"or"B"|x=10]?

b) If p[y="A"|x=4]=0.25, how many hours do we need to study so that p[y="A"|x=?]=0.99?