Clara and Gloria are selling pies for a school fundraiser.  Customers can buy apple pies and lemon meringue pies.  Clara sold 6 apple pies and 4 lemon meringue pies for a total of $80.  Gloria sold 6 apple pies and 5 lemon meringue pies for a total of $94.  What is the cost each of one apple pie and one lemon meringue pie? Solve by substitution not by elimination