China will invest $50 billion to help overhaul Brazil’s aging infrastructure, Brasilia said Thursday, ahead of an official visit by Chinese Prime Minister Li Keqiang. “There are $50 billion in new projects,” said Jose Graca Lima, Brazil’s undersecretary of state, who oversees Asia and Oceania. Battling a fifth straight year of poor growth and mired in a bruising graft scandal involving state oil giant Petrobras, Brazil is seeking to revamp its sagging infrastructure ahead of next year’s Rio Olympics, the first Games to be held in South America. A Brazilian government source said Brazil, Latin America’s biggest economy, was determined to overhaul its dilapidated roads, railways, airports and ports ahead of the Olympics. China has been Brazil’s chief trading partner since 2009 and one of its main sources of foreign investment.