ss="va">arr_delay</span> <span class="op">-</span> <span class="va">dep_delay</span><span class="op">)</span> <span class="op"><a href="https://magrittr.tidyverse.org/reference/pipe.html" class="external-link">%&gt;%</a></span></span>
<span>  <span class="fu"><a href="../reference/mutate.html">mutate_dt</a></span><span class="op">(</span>gain_per_hour <span class="op">=</span> <span class="va">gain</span> <span class="op">/</span> <span class="op">(</span><span class="va">air_time</span> <span class="op">/<