Question

A cheetah spots a gazelle 300 meters away. The cheetah begins to chase the gazelle at a rate of 18 meters per second at the same time the gazelle begins to run aways at a rate of 16 meters per second. Which equation represents the time, t, for the cheetah to reach the gazelle?

Answer 1

The cheetah runs 2 meters/sec faster than the gazelle.  Eventually the cheetah will overcome the gazelle.  Since distance = rate times time, time = distance/rate.

Thus, 

300 meters / (2 meters/sec) = 150 sec = 2 min 30 sec