In an engineering test, a rocket sled is propelled into a target. The sled’s distance d in meters from the target is g

In an engineering test, a rocket sled is propelled into a target.  The sled’s distance  d in meters from the target is given by the formula  d = -1.5 t ² + 120, where  t is the number of seconds after rocket ignition.  How many seconds have passed since rocket ignition when the sled is 10 meters from the target?