Such that the number of potential refugees A changes with the change, when the closer the S D, C is closer to 0, the resulting value is smaller, the fewer changes refugees. Then D into the original equation:
The number of potential refugees varies with A, and the closer S approaches To D, the closer C is to 0, the smaller the value obtained and the less the number of refugees changes. Then bring D into the original equation to get:
The number of potential refugees changes with the change of A. the closer s is to D, the closer C is to 0, the smaller the value and the less the change of refugees. Then D is taken into the original equation to get: