Bangladesh would attain 8.0 percent GDP (gross domestic product) growth in the next three years should the country`s investment-to-GDP ratio increases to 34.0 percent, World Bank Chief Economist Dr. Kaushik Basu said.With 6.5 percent GDP growth, the current investment-to-GDP ratio is 29.0 percent, the economist said, after a meeting with Finance Minister Abul Maal Abdul Muhith at his official residence in the capital city on Monday.Referring to the World Bank`s economic outlook for Bangladesh, Basu, also senior vice-president (development economics) of the multi-donor agency, said the country would achieve 6.7 percent GDP growth next year.He said the country made remarkable progress in many areas, including per capita income and human resources development, but still it would require going far and there would be huge challenges."The main challenge is the infrastructure development", he added.Basu came to Dhaka on December 12 on a 5-day visit at the invitation of Bangladesh Bank (BB) Governor Dr. Atiur Rahman. He is scheduled to join a press conference tomorrow (Tuesday) at 4pm at BICC to be organised jointly by the World Bank and Bangladesh Bank.