Hey there, thanks for dropping by...
Let me get straight into your questions
-should I apply to any top 10 school anyway? The only way you would have a chance is if your work experience is really exceptional - I mea if those two companies you sold are huge, yeah maybe. Otherwise applying with a 550 is suicide. I know you really don't want to, but still you should think about retaking if you REALLY want to do this MBA. I mean, from first glance your WE looks very very good. So you'd have a shot. But not with a 550.
-should I apply to any US b-school on 3rd or 4th round at all?
You wouldn't get into any that would be worth the money.
-should I only focus on the Europe b-schools, that are more flexible and with an older age average?
Not only!! But yes it's a good idea to think about european schools. You can also look at the best US EMBA program,s which might fit your needs I feel. Whatever you do, you still need a better GMAT.
-which are the b-schools mainly focus on entrepreneurship and in which my profile would fit in more accordingly?
Pretty much all schools have entrepreneurship in their program - INSEAD, Cambridge, Oxford, Babson would be places to start looking at.
Hope this helps! And let me know if you have any follow up questions.
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