3> 45 degree line would be the set of pareto efficient points. so option "c"
i.e x1=y1 for x1 belongs to [0,1000]
4>again 45 degree line will give the set of competitive eq allocation. so option "c"
5>both are pareto efficient as both points lies on the band which shows pareto efficient allocations.. (hint: draw edgewrth box)
6>option c
refer to the following link to understnd it in a better way>
http://discussion-forum.2150183.n2.nabble.com/how-to-solve-for-competitive-equillibrium-td5269273.html#a5273779
:)