$**4\mathrm{.}1\mathrm{.}9$ Your boss asks you to calculate the flow through a natural$-$gas pipeline. Since it is $26$ in$.$ in diameter, it is impossible to run the gas through any kind of meter or measuring device. You decide to add $100lb$ of $C{O}_2$ per minute to the gas through a small $\frac{1}{2}$ in$.$ piece of pipe, collect samples of the gas downstream, and analyze them for $C{O}_2.$ Several consecutive samples after $1hr$ are given in the following table.

$\backslash$table$[[$Time$,\%C{O}_2$