Java Programming

I really need help with this, I've been searching for an answer all day and have found nothing.
This is the original program and I'm trying to make it so instead of stoppingDistance having to be equal to tailgateDistance for it to print minor wreck, it will allow a range of 40 feet. Like a range of uncertainty of plus or minus 20 feet, and I need to use a named constant that is: RANGE = 40.0


import java.util.Scanner;

public class StoppingA
{
public static void main(String[] args)
{
Scanner stdIn = new Scanner(System.in);
double speed; // speed car is traveling;
double tailgateDistance; // distance from other car;
double stoppingDistance; // calculated distance

System.out.print ("Enter your speed (in mph): ");
speed = stdIn.nextDouble();
System.out.print ("Enter your tailgate distance (in feet): ");
tailgateDistance = stdIn.nextDouble();

stoppingDistance=speed*(2.25+speed/21);

if (stoppingDistance < tailgateDistance)
{
System.out.println("No problem.");
}
else if (stoppingDistance == tailgateDistance)
{
System.out.println("Minor wreck.");
}
else if (stoppingDistance > tailgateDistance)
{
System.out.println("Major wreck!");
}


} // end main
} // end class StoppingA

Edited by: Ensanvoration on Feb 23, 2010 3:31 PM