BonusWage

import java.util.Scanner;
import java.io.*;
 
class BonusWage { 
	public static void main (String [] args ){
		Scanner input = new Scanner(System.in);
		int hours, extrahours;
		double wagerate,total,bonus;
 
 
		System.out.println("Enter your wage rate: ");
		wagerate = input.nextDouble();
		System.out.println("Enter the amount of hours you worked: ");
		hours = input.nextInt();
		extrahours = hours -30;	
 
		if (hours > 30) {
			bonus = extrahours*(wagerate*1.5);
			total = bonus + ((hours-extrahours)*wagerate);
			System.out.println("Your wage will be: " + total);
		}
 
		else if (hours >= 0) {
		total = wagerate*hours;
		System.out.println("Your wage will be: " + total);

		}

		else if (hours < 0) {
		System.out.println("That is not possible!");
		}
	}
}

Recomiendo que en los condicionales explícitamente pongas el rango: Por ejemplo (hours >= 0 && hours <= 30) para delimitarlo mejor y no pase algo raro.