Question

A body wieghs 75 gf in air, 70.5 gf in waterand 66 gf in a liquid, calculate the density of the liquid.

Answer 1

relative density of liquid

     = density of liquid / density of water
     = buoyancy force in liquid / buoyancy force in water
     = Loss of weight in liquid / loss of weight in water
     = [ weight of object  in air - weight of object in liquid ] / [ weight of object in air - weight of object in water ]

     = [ 75 - 70.5 ] / [ 75 - 66 ]
     = 4.5 / 9
     = 0.5

Density of liquid = 0.5 * density of water
             = 0.5 * 1000 kg / m^3
                 =  500 kg/m^3

Answer 2

relative density of liquid

     = density of liquid / density of water
     = [ weight of object  in air - weight of object in liquid ] / [ weight of object in air - weight of object in water ]
so using this derivation caliculate the answer