China shares tumble to 3-week low, Hong Kong to snap winning streak
By: Clement Tan
*China Unicom slumps 7 pct after Q3 earnings disappoint. *Bank of China climbs after positive earnings. HONG KONG, Oct 26- China shares tumbled to a three week low on Friday, dragging down Hong Kong markets, as investors took profits on recent outperformers ahead of several key third quarter corporate earnings from major resources companies.