def averages(grades):
    '''
    (list of list of number) -> list of float

    Return a new list in which each item is the average of the
    grades in the inner list at the corresponding position of
    grades.

    >>> averages([[70,75, 80], [70,80,90,100], [80,100]])
    [75.0, 85.0, 90.0]
    '''

    averages = []

    for grades_list in grades:
        # Calculate the average of grades_list and append it
        # to averages

        total = 0
        for mark in grades_list:
            total = total + mark

        averages.append(total / len(grades_list))
    return averages

def mystery(lst):
    for sublist in lst:
        total = 0
        for num in sublist:
            total = total + num
    return total

def averages(grades):
    '''
    (list of list of number) -> list of float

    Return a new list in which each item is the average of the
    grades in the inner list at the corresponding position of
    grades.

    >>> averages([[70,75, 80], [70,80,90,100], [80,100]])
    [75.0, 85.0, 90.0]
    '''

    averages = []

    for grades_list in grades:
        # Calculate the average of grades_list and append it
        # to averages

        total = 0
        for mark in grades_list:
            total = total + mark

        averages.append(total / len(grades_list))
    return averages

def mystery(lst):
    for sublist in lst:
        total = 0
        for num in sublist:
            total = total + num
    return total

(list of list of number) -> list of float      Return a new list in which each item is the average of the     grades in the inner list at the corresponding position of     grades.      >>> averages([[70,75, 80], [70,80,90,100], [80,100]])     [75.0, 85.0, 90.0] # Calculate the average of grades_list and append it # to averages