The Wizard of Oz and Dorothy leave the Emerald City in a hot air balloon, rising vertically at a speed of 15 feet per second. When they are 60 feet above the ground, Dorothy accidentally drops her basket. (Thankfully, Toto was not in it at the time.)

Assume that in the land of Oz, gravity is only 10 feet per second per second, but still downward.

How many seconds after she drops her basket will it land on the ground?

Upload a .pdf file that has your full solution to only this question, and also enter the exact amount of time (no approximations).