A ship takes 18 days to reach its designated part. It starts with food for its crew of 450 men at the rate of 720gm per day per head. After 11 days of its journey they rescued 180 passangers from a sinking ship. While rescuing the captain noticed a technical problem in the ship's engine, and estimated the ship would reach the destination after 9 days. How much food should they now consume per day per head so that it lasts for the rest of the journey.