\(\lambda_s \sqrt{\frac{C+V}{C-V}}=\lambda_0 \Rightarrow \lambda_s \sqrt{\frac{C+V}{C-V}}=\left(1+\frac{0.02}{100}\right) \lambda_s\)

\(\frac{C+V}{C-V}=\left(1+\frac{0.02}{100}\right)^2 \Rightarrow \frac{C+V}{C-V}-1=\frac{0.04}{100} \Rightarrow \frac{2 V}{C-V}=\frac{1}{2500}\)

\(\text { or } V=\frac{3 \times 10^5}{5001}=60 \,km / s\)