A ship left a port and headed due west, having 400 pounds of food for the journey's supply. After one day of sailing, 2/5 of the supplies had been used by the sailors in the ship. After another two days of sailing, the sailors used 3/5 of the remaining supplies. Calculate the number of supplies remaining in the ship to last the sailors until they dock.
Please reason step by step, and put your final answer within \boxed{}.
user