MASS of body in vacuum. APPARENT weight of the body in air = Apparent weight of standard WEIGHTS in air \[\RIGHTARROW \] Actual weight ? upthrust due to displaced air = Actual weight ? upthrust due to displaced air \[\Rightarrow \]\[{{M}_{0}}g-\left( \FRAC{{{M}_{0}}}{{{d}_{1}}} \right)\,dg=Mg-\left( \frac{M}{{{d}_{2}}} \right)\,dg\] \[\Rightarrow {{M}_{0}}=\frac{M\left[ 1-\frac{d}{{{d}_{2}}} \right]}{\left[ 1-\frac{d}{{{d}_{1}}} \right]}\]