Calculating hammer price to limit on auction with variable commission rates

auction_prices.rb

BEFORE  = 0.25  # Percent commission before the limit 
LIMIT   = 50000 # The commission boundary
AFTER   = 0.20  # Percent after the boundary

# The only number to change is this one! No spaces, dots or commas...!
total_price_including_commssion = 10000000

# Warning - Do not use for bids over a £1,000,000 Hammer

def finds_the_total_price_including_commission(hammer)
  if hammer < LIMIT
    commission    = BEFORE * hammer
  else
    commission    = BEFORE * LIMIT
    passed_limit  = hammer - LIMIT
    commission    = commission + (AFTER * passed_limit)
  end
  return hammer + commission
end

def finds_the_hammer_price(total_price_including_commssion)
  total_price_including_commssion.to_i.times do |count|
    total = finds_the_total_price_including_commission(count)
    if (total > (total_price_including_commssion - 1.0)) && (total < (total_price_including_commssion + 1.0))
      return count
    end
  end
end

hammer_price  = finds_the_hammer_price(total_price_including_commssion)
total_price   = finds_the_total_price_including_commission(hammer_price)

puts "Hammer Price:\t\t#{hammer_price}"
puts "Commission:\t\t#{total_price - hammer_price}"
puts "Total Price:\t\t#{total_price}"