C :

#include <stdio.h>
 int main()
 {
 	double a,b,c;
 	scanf("%lf",&a);
 	scanf("%lf",&b);
 	scanf("%lf",&c);
 	printf("%.1lf",(a*0.2+b*0.3+c*0.5));
 	return 0;

 }

C++ :

#include <bits/stdc++.h>
#define int long long
using namespace std;
typedef long long LL;
typedef pair<int,int> PII;
const int MAX32=2147483647;
void solve()
{
    double a,b,c;
    cin>>a>>b>>c;
    double ans = (a*2+b*3+c*5)/10;
    printf("%.1lf",ans);
}
signed main()
{
    // ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
    int t;
    t=1;
    // cin>>t;
    while (t--)
    {
        solve();
    }
}

Java :

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        double low = 0;
        double up = 10.0;
        Scanner scanner = new Scanner(System.in);
        double A = scanner.nextDouble();
        double B = scanner.nextDouble();
        double C = scanner.nextDouble();
        if (A >=low && A<=up && B>=low && B<=up && C>=low && C<=up) {
        double number = A * 0.2 + B *0.3 +C * 0.5;
            System.out.println(String.format("%.1f",number));
        }
    }
}