By Eva Mathews and Nivedita Balu and Hyunjoo Jin Reuters (Corrects second paragraph to say price hikes, adds dropped word "to") July 28 (Reuters) – Tesla Inc showed signs this week of divergent strategies in the world's two biggest automotive markets, raising prices to boost profit margins in the United States while keeping prices steady in China and hoping to grow sales there. Tesla raised prices for the most affordable versions of Model 3 and Model Y about a dozen times this year in the United States, according to data tracked by Reuters. At the same time, Tesla recently introduced…