Procter & Gamble Co. bought the remaining 20% stake of its China joint venture for $1.8 billion, securing its foothold in one of the world’s fastest growing economies. The purchase accelerated P&G’s plan to take over the venture from partner Hutchison Whampoa China Ltd. In a statement, P&G said results from its China business give it confidence that it has the right people, the right business strategies and the in-depth understanding of local consumers and retailers to...