Highest Speculated Biggest Economy in Africa By 2049.

Taking a closer look at Africa's growing rate, the population is set to double by 2049, hence unlocking the economic potential of the continent’s diverse regions will be vital to create the millions of jobs needed.
Africa’s gross domestic product growth has grown to 4.5% in 2015 from 3.9% in 2014 and is expected to strengthen to 5% in 2016. West Africa achieved high growth of 6% in last year despite its battle with the Ebola virus. Nigeria GDP experienced a growth of 6.3% which mainly came from non-oil sectors showing
that the economy is diversifying. But Southern Africa’s growth fell below 3% as the key South African economy only grew by 1.5%.

Many African countries have improved their investment climate and conditions for doing business which enhance long-term growth prospects. Benin, Côte d’Ivoire, Democratic Republic of the Congo, Senegal and Togo are top ten countries worldwide with the most reforms making it easier to do business.

Over the next 30 years, more than half of the world’s births will happen in Africa continent. It means that over the same time period, the region’s working age population is expected to triple to 1.25 billion people.
With the right policies in place, it could be harnessed into increased savings and investments, thus leading to a booming economic growth.

Taking a closer look at Ethiopia Africa’s third most populous, has posted blistering economic growth in the past decade or so. It is fast closing the infrastructure gap, laying down a flurry of roads, railways and power projects which would give it a competitive advantage in the region. Ethiopia has the advantage of an efficient bureaucracy and stable authoritarian political regime, though this could prove to be a liability in the future as people demand more political space which in this study of Ethiopia doesn't seem to likely occur.

So you might have to have a look at what Ethiopia has to offer in the near future.