The sum of numbers in a line from a file

[kjakupak at gmail.com]

What I've got is 
def stu_scores():
    lines = []
    with open("file.txt") as f:
        lines.extend(f.readlines())
    return ("".join(lines[11:]))

scores = stu_scores()
for line in scores:
    fields = line.split()
    name = fields[0]
    sum1 = int(fields[4]) + int(fields[5]) + int(fields[6])
    sum2 = int(fields[7]) + int(fields[8])
    average1 = sum1 / 3.0
    average2 = sum2 / 2.0
    print ("%s %f %f %") (name, average1, average2)

It says that the list index is out of range on the sum1 line. I need stu_scores because the table from above starts on line 11.