If P8 and P9 represent the population of West African in 1978 and 1979 respectively, and given that in 1979.
D= number of deaths, B= number of births, I= number of immigrants, E= number of Emigrants. Then the size of the population in 1979 is given by
- P9 = P8 + D - B = I - E
-
P9 = P8 + B - D + I - E
- P9 =P8 + B - D + E - I
- P9 = B - D + I - E
- P9 = P8 + B + D + I + E