lass="comment">// P(X &gt; 3.1)</span>

<span class="keyword">double</span> <span class="identifier">under_weight</span> <span class="special">=</span> <span class="number">2.9</span><span class="special">;</span>
<span class="identifier">cout</span> <span class="special">&lt;&lt;</span><span class="string">"fraction of packs &lt;= "</span> <span class="special">&lt;&lt;</span> <span class="identifier">under_weight</span> <span class="special">&lt;&lt;</span> <span class="string">" with a mean of "</span> <