C :

#include<stdio.h>

int main()
{
	float a,b;
	scanf("%f",&a);
	if(a<=10){
		b=a*1.50;
		printf("%.2f",b);
	}else{
		b=(a-10)*1.20+10*1.5;
		printf("%.2f",b);
	}
	return 0;
}

C++ :

#include <iostream>
#include <cstdio>
using namespace std;
int main()
{
    double weight,ans;
    cin>>weight;
    if(weight<=10)
    {
        ans=weight*1.5;
    }
    else
    {
        ans=10*1.5+(weight-10)*1.2;
    }
    printf("%.2lf\n",ans);
    return 0;
}