Howard started studying how the number of branches on his tree grows over time.
The relationship between the elapsed time $t$, in years, since Howard started studying the tree, and the number of its branches, $N(t)$, is modeled by the following function:
###$N(t)=38\cdot \left(\dfrac{9}{5}\right)\^{\Large \frac{t}{7.3}}$
**Complete the following sentence about the rate of change in the number of branches.**
Howard's tree gains $\dfrac{4}{5}$ more branches every [[☃ numeric-input 1]] years.