两军交锋 hdu2548 水题

#include <iostream>
using namespace std;

int main(){
#ifndef ONLINE_JUDGE
freopen("2548in.txt","r",stdin);
#endif
int t;
double u,v,w,l;
scanf("%d",&t);
while (t--){
scanf("%lf%lf%lf%lf",&u,&v,&w,&l);
printf("%.3lf\n",l/(u+v)*w);
}
return 0;
}