Vietnam, South Korea sign free trade agreement   Vietnam has signed with South Korea a free trade agreement which is expected to boost its exports to the South Korean market, the Vietnamese government said on Tuesday. The signing in Hanoi concluded two-year talks between the two countries and the agreement is expected to enable their trade to reach $70 billion a year by 2020, the government said in a statement, citing Vietnam's trade minister Vu Huy Hoang. South Korea is the biggest investor in Vietnam, with pledges totaling $38 billion in more than 4,200 projects as of March 2015, based on Vietnam government data. Reuters