Water washed by three people for 40 minutes =3×40= 120;

6 people 16 minutes of elutriation water =6× 16=96 portions;

Water leaking into the ship every minute = (120-96) ÷ (40-16) =1serving;

Raw water in the ship = 120-40× 1=80 copies;

Time required for 5 people to wash water =80÷(5- 1)=20 minutes.