Find the uncertainty in position
The question tells you
\begin{aligned}
&amp;&amp;v&amp;=3\cdot10^7\:\mathrm{m/s}\pm1\%\\
&amp;&amp;\Delta v &amp;= |(v+1\%v) - (v-1\%v)|\\
\implies&amp;&amp;\Delta v &amp;= \frac{2}{100}v\\
\therefore&amp;&amp;\Delta v&amp;= 2\cdot3\cdot10^5\:\mathrm{m/s}
\end{aligned}

Hence
\begin{aligned}
&amp;&amp;\Delta x\cdot\Delta p &amp;\geq \frac{\hbar}{2}\\
\implies&amp;&amp;\Delta x\cdot\Delta (v\cdot m) &amp;\geq \frac{\hbar}{2}\\
\implies&amp;&amp;\Delta x&amp;\geq \frac{\hbar}{2\cdot\Delta v\cdot m }\\
\therefore&amp;&amp;\Delta x &amp;\gtrapprox\frac{1.05\cdot10^{−34}\:\mathrm{J\cdot s}}{2\cdot6\cdot10^5\:\mathrm{m/s}\cdot1.6\cdot10^{−27}\:\mathrm{kg}}\\
&amp;&amp;\Delta x&amp;\gtrapprox5.5\cdot10^{-14}\:\mathrm{m}\\
\end{aligned}