Answer 1: The entire diagonal will be the contract curve.
Answer 2: Pareto Superior allocation makes atleast one person better off as compared to the initial endowment point. Here Bob has initial endowment (10,10) and his utility function can be considered as U=x+y with an initial utility level of 20, similarly eric has an initial endowment of (10,20) with the utility function U=Min{x/a,y/b} where a/b=3/2=1.5 with an initial utility level of 10, clearly Eric has 5 extra amount of y then is needed, so what he can do is that he can trade this y for x till he reaches an utility level higher than the original one. In this case if he trades 2 units of y for 2 units of x, his new utility will be U=Min{12,18}, clearly now x and y are in the ratio 3/2 and Eric's utility is increased to 12. So such an allocation will be considered as a Pareto Superior move where atleast one agent is made better off without making the other worse off, see here that due to the aforesaid reallocation Bob gets (8,12) and is on the same utility level of 20 while eric moves on to the utility level of 12. Thus this is a Pareto Superior move.
Answer 3: From the previous part it can be easily said that the price ratio should be (px/py)=1.
Akshay plz check.
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