Apark ranger is to restore the plant cover in a valley after a forest fire. he launches a cluster of seeds from a high point above the valley. the cluster's height above the valley floor can be modeled using the function given below. h(t)= -4t^2+64t+320 how many seconds will it take for the seed cluster to reach the valley floor? a.320 seconds b.4 seconds c.20 seconds d.16 seconds e.64 seconds

The cluster's height above the valley floor can be modeled by the equation:



When the cluster seeds will reach the valley floor, the height of the cluster seeds above the valley floor will be 0. So substituting h(t) = 0 in the above equation we can find the time when the cluster seeds will reach the valley floor. 



Since t represents the amount of time, it cannot have a negative value. So the only acceptable value of t is t=20

Thus it will take 20 seconds for the cluster of seeds to reach the valley floor. Thus the correct answer is option C