As shown below, range only supports integers:
>>> range(15.0)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: range() integer end argument expected, got float.
>>> range(15)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]
>>>
However, c/10 is a float because / always returns a float.
Before you put it in range, you need to make c/10 an integer. This can be done by putting it in int:
range(int(c/10))
or by using //, which returns an integer:
range(c//10)