It's the end of June and you've outdone yourselves again! Our mailbag is full and we've got a packed show. Today David tackles how to build a new portfolio from scratch, considers whether to sell or add to losers, and attempts to solve an ancient, riddle that left Plato pondering. All that and more on this week's mailbag. Thanks to Harry's for supporting The Motley Fool. Get your Free Trial — go to Harrys.com/fool

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