I believe the code to be correct although it seems to be subtracting 50 from the days cost returning a result of -10 the exact error message I get is below.
Oops, try again. It looks like rental_car_cost returns -10 instead of the correct amount (40) for 1 days.
I believe it is meant to return back to me 40
def rental_car_cost(days): cost = days * 40 if days <= 7: return cost - 50 elif days <= 3 and days >= 7: return cost - 20 else: return cost