sorry that was a bit too much of a rush. you have to update the b at
each stage as in the following.
#include <admodel.h>
main()
{
int n=25;
double Binit=1000;
double C=500;
double B=Binit;
for (int i=1;i<=n;i++)
{
B=B/(1.0+C/(n*B));
}
cout << Binit-B << " " << C << endl;
}