A solid weighs 1000g in air , 75g in water, and 70g in oil. Calculates the relative density of oil ?

Answer 1

mass of water displaced = 1000 - 75 = 925 g so if the water density is 1 g/ cm^3 its volume is 925 cm^3

the mass of oil displaced is rho*925 g
so
rho*925 = 1000 - 70
= 930 g
so
rho = 1.0054 g/cm^3

Strange oil. Most oil floats on water.