7-11 calculation of residential water charges by sections

7-11 Calculate the water charge of residents by sections (10 branch )

To encourage residents to save water , Water companies adopt the method of pricing according to the water consumption , Residents should pay for water y（ element ） And monthly water consumption x（ Tons of ） relevant ： When x No more than 15 Ton time ,y=4x/3; Beyond ,y=2.5x−17.5. Please write a program to calculate the water charge .

Input format ：

The input gives a nonnegative real number on one line x.

Output format ：

Export the water charge in one line , Accurate to the decimal point 2 position .

sample input 1：

12

sample output 1：

16.00

sample input 2：

16

sample output 2：

22.50

#include<stdio.h>
int main(){
    float x;
    double y;
    scanf("%f",&x);
    if(x <= 15){
        y=4*x/3.0;
    }else{
        y=2.5*x-17.5;
    }
    printf("%.2f",y);
    return 0;
}