#### Example 1.99.

Which grow faster, Hybrid A wheat seedlings, which grow 11.2 centimeters in 14 days, or Hybrid B seedlings, which grow 13.5 centimeters in 18 days?

## Solution.

We compute the growth rate for each strain of wheat. Growth rate is expressed as a ratio, \(\dfrac{\text{centimeters}}{\text{days}}\text{,}\) or centimeters per day. The growth rate for Hybrid A is

\begin{equation*}
\frac{11.2 \text{ centimeters}}{14 \text{ days}}= 0.8 \text{ centimeters per day}
\end{equation*}

and the growth rate for Hybrid B is

\begin{equation*}
\frac{13.5 \text{ centimeters}}{18 \text{ days}}= 0.75 \text{ centimeters per day}
\end{equation*}

Because their rate of growth is larger, the Hybrid A seedlings grow faster.