\( \frac{{\Delta v}}{v}\,\, \times \,\,100\,\, = \,\,\frac{{\Delta r}}{r}\,\, \times \,\,100\,\, + \;\,\frac{{\Delta \ell }}{\ell }\,\, \times \,\,100 \)
\( = \,2\,\,\frac{{0.01}}{2}\,\, \times \,\,100\,\, + \;\,\frac{{0.1}}{5}\,\, \times \,\,100\,\, = \,\,1\,\, + \;\;2\,\, = \,\,3\% \)