#include <stdio.h>
double Proportion(int Amount[2],double Concentration[2]) {
    return ((Amount[0]*Concentration[0]+Amount[1]*Concentration[1])/(Amount[0]+Amount[1]))*100;
}
int main() {
    double C[2] = {0.6,0.43};
    int A[2] = {90,200};
    printf("%f\n",Proportion(A,C));
    return 0;
}//by春寿