Darlene is making a quilt that has alternating strips of regular quilting fabric and sateen fabric. The sateen fabric costs $6 per yard and the quilting fabric costs $4 per yard. She spends $76 on a total of 16 yards of the two fabrics at a fabric store. Write a system of equations that can be used to find the amount x (in yds) of regular quilting fabric and the amount y (in yards) of sateen fabric she purchased. Then determine how many yards of each fabric she bought.