C++ :

#include<bits/stdc++.h>
using namespace std;
int main(){
	double a,b,c,d,e,f;
	cin>>a>>b>>c>>d;
	e=a*b+c*d;
	f=e/(b+d);
	printf("%.1f",f);
	return 0;
}

Python :

# coding=utf-8
a=input().split()
for i in range(len(a)):
    a[i]=float(a[i])
sum1=round((a[0]*a[1]+a[2]*a[3])/(a[1]+a[3]),1)
print(sum1)