Rounding decimals in Python (or: Why doesn't .5 round to 1?)

Doing my morning Hacker Rank puzzle this morning, I discovered Python 3 doesn't round numbers ending in .5 the way I'd expect:

int(12.5)
>>> 12
int(13.5)
>>> 14
round(12.5)
>>> 12
round(13.5)
>>> 14

As always, Stack Overflow had the answer: Python rounds .5 down sometimes because of Banker's Rounding, also known by the much more informative name "Round Half To Even". Python will round .5 numbers to the nearest even whole.

In the problem I was solving (giving a rounded total cost of a meal), this didn't work, so I had to use decimal.Decimal's quantize method to round up:

from decimal import Decimal

mc = float(input())  # these unpythonic variable names came from HackerRank
tp = int(input())
tax = int(input())

def totalCost(mc, tp, tax):
total = Decimal(mc + (tp / 100 * float(mc)) + ((tax / 100 * float(mc)))).quantize(Decimal('1'))
print("The total meal cost is {} dollars.".format(total))

totalCost(mc, tp, tax)

I'm over 80 characters in that line, so there's the potential for refactoring.