糖水

#include <iostream>
using namespace std;
int main(int argc, char** argv) {
    float tang,shui,tangshui;
    tang=15*0.2;
    tangshui=tang/0.15;
    shui=tangshui-tang;
    cout<<"应加水:"<<shui-15*0.8;
    return 0;
    
}