A lake water at $15C$ is low in dissolved oxygen $(1\mathrm{.}5m\frac{g}{L}DO$ and is aerated in a fountain aerator. Droplets averaging $0\mathrm{.}8cm$ in diameter are released. For a mass transfer coefficient in the liquid phase $(k_L)$ of $120c\frac{m}{h}r,$ and assuming that almost all of the resistance to oxygen transfer is in that phase, find the time $($seconds$)$ that a droplet would have to be in the air to increase the DO concentration to $7\mathrm{.}25m\frac{g}{L}$ before it re$-$enters the bulk solution.