DSE 2014 Question 8: General equilibrium and exchange economies

Consider an exchange economy with two agents, 1 and 2, and two goods $X$ and $Y$. Agent 1's endowment is $(0,10)$ and Agent 2's endowment is $(11,0)$. Agent 1 strictly prefers $(a,b)$ to $(c,d)$ if $a>c$, or $a=c$ and $b>d$ (lexicographic, $X$ first). Agent 2 strictly prefers $(a,b)$ to $(c,d)$ if $\min\{a,b\}>\min\{c,d\}$. Suppose only agent 2's preferences are changed so that they become identical to those of agent 1. Then,