Harry的题解

https://www.excalidraw.com

代码可AC

#include <bits/stdc++.h>
using namespace std;

int main()
{
    double a,b,c;
    cin>>a>>b>>c;
    cout << a*0.2+b*0.3+c*0.5;
    return 0;
}

注意用double
%20=0.2
%30=0.3
%50=0.5