An observer $\displaystyle {559}$ feet away watches a hot air balloon ascent straight up from the ground to a certain point in $\displaystyle {32}$ minutes. At that time, the angle of elevation to the hot air balloon was $\displaystyle {13.8}^{\circ}$. At what speed, in miles per hour, did the hot air balloon ascend, rounded to the nearest hundredth?

 $\displaystyle {s}=$  mph.