a
\(\frac{24- P _{ s }}{ P _{ s }}=\frac{ m \times 18}{1000}\)

wt of solute \(=30\,gm\)

Volume of solution \(=100\,mL\)

wt. of solution \(=1.2 \times 100=120\,gm\)

wt. of solvent \(=120-30=90\,gm\)

\(m =\frac{30 \times 1000}{180 \times 90}=1.85\)

\(\frac{24- P _{ s }}{ P _{ s }}=\frac{1.85 \times 18}{1000}\)

\(24- P _{ s }=0.0333 P _{ s }\)

\(P _{ s }(1.033)=24\)

\(P _{ s }=23.22\)