Hello vaibhav.. :)
for the given economy, a competitive allocation is tht allocation where,
1>for a given price, each consumer is maximising his utility such tht value of endownmnt equals value of good they are demanding.. and
2>demand = supply for all commodities.. (or markets clear)
You can either plot IC in edegeworth box or
you can simply find out individual demand and then check at what price ratio , demand by both of them = endownment
:)