You divide $1.20 by 18 to get the amount per piece which is about $0.067. Then you multiply 0.067 by 27 for the amount for 27 pieces which is about $1.81 rounded to $1.80.
Since jason is currently at 54 feet above sea level and David is 11 feet below sea level the add 11 plus 54 which would give you 65 feet is there distance of elevations
