the equation y=-16t2+120 can be used to represent the fruits height above the ground, where t represent time ,in seconds, after she threw the apple

2 answers

Well, actually she seems to have dropped it from 120 feet up or threw it horizontally.
If she threw it with any initial vertical speed Vi the equation would have been:
y = -16 t^2 + Vi t + 120
16 is about 1/2 of g in English units.
In general
y = -(1/2) g t^2 + Vi t + Hi
BUT
you did not ask any question.
Y = 120 - 16t^2 = 0 When the fruit hits gnd.
120 - 16t^2 = 0,
16t^2 = 120,
t = 2.74 s. = Time required for fruit to hit gnd.