Mali is 31% larger than Tanzania.
Area: 1,240,192 km2 World Factbook
Population: 16,455,903 (July 2014) World Factbook
Mali, officially the Republic of Mali, is a landlocked country in West Africa. Mali is bordered by Algeria to the north, Niger to the east, Burkina Faso and Ivory Coast to the south, Guinea to the south-west, and Senegal and Mauritania to the west. Wikipedia
Area: 947,300 km2 World Factbook
Population: 49,639,138 (July 2014) World Factbook
Tanzania, officially the United Republic of Tanzania, is a country in East Africa in the African Great Lakes region. It is bordered by Kenya and Uganda to the north; Rwanda, Burundi and the Democratic Republic of the Congo to the west; and Zambia, Malawi and Mozambique to the south. Wikipedia