Conventional price elasticity of demand is a simplistic and elementary formula that has mathematical and economic deficiencies when applied to price (rates) and demand (balances) of deposit products: It does not recognize inverse relations between price and demand.
At its peak in 1300, the Mali Empire covered an area about twice the size of modern-day France and stretched to the west coast of Africa. In the late 19th century, during the Scramble for Africa, France seized control of Mali, making it a part of French Sudan.
The Mali Empire had a more stable economy. The Mali Empire eventually stretched from the Atlantic coast south of the Senegal River to Gao on the east of the middle Niger bend. It included the great cities of Timbuktu, Djenne, and Gao on the Niger River, the salt mines of Taghaza, and the gold fields of Bumbuk and Bure. Like Ghana before it, Mali collected taxes on trade throughout the empire.