Hi
Most universities will give a country by country breakdown or requirements. As far as I understand it a 3.5/5.0 is the absolute minimum you need as that is what universities consider to be closest to a UK 2:1. The grading system is different across Africa, many states use the UK system of a 1:1, 2:1, etc, so you can't ask how they convert 'African' degrees. Also, the 3.5 requirement varies country to country - I know an example where my old Uni would accept 3.5 from a Nigerian student, but a Ugandan had to have a 3.6 minimum.