A boat having a length 3 metre and breadth 2 metre is floating on a lake. The boat sinks by one cm when a man gets on it. The mass of the man is

Additional volume of liquid displaced =3×2×1100m3=350m3 Additional upthust =350×1000kg weight =60kg weight  This must be equal to the weight of m g of the man ∴ mg=60kg weight or m=60kg