The problem is; Africa population will be very high (high population density) leading to difficulty of the governments to feed their population hence making it unsustainable.
Solution 1; promote family planning methods through intense advertisement
Solution 2; increase literacy rates of the population by increasing education facilities and the quality of education.
Likely results of solution 1; the most common form of family planning method that will be used will be contraceptives. This will eventually reduce the population growth rate, directly.
Likely results of solution 2; Research has shown that educated/ literate couples are inclined to have smaller families which they can financially cater for. This, therefore, will gradually and indirectly lead to reduced growth rates in the pollution.
The best solution is Solution 2 because it kills two bird with one stone. It increases literacy levels in the pollution while also indirectly promoting reduce population growth. Solution 1 may not be as effective because African culture may not allow most to use contraception as a means of family planning.