saving.py

INTEREST_RATE  = [5, 7]
ANNUAL_SAVINGS = [40, 50, 60]
YEARS          = [10, 15, 20]

def calculate_total(interest, savings, years):
    interest = 1. + interest / 100.
    return sum([savings * (interest ** i) for i in range(years)])

for interest in INTEREST_RATE:
    for savings in ANNUAL_SAVINGS: 
        for years in YEARS:
            total = calculate_total(interest, savings, years)
            total = int(total)
            print "{1}k for {2} years at {0}%: {3}k".format(interest, savings, years, total)
        print ""
    print "-"*25