A rocket on a computer screen has a path modeled by the equation h=-t2+3t+10 where t is time in seconds and h is the height above a platform and is in computer units. Find how long the rocket takes to reach the platform.

A - 2 seconds

B - 10 seconds

C - 12 seconds

D - 5 seconds

When the rocket reaches the platform, then h must be equal to 0

h=0

Calculating for t using the equation:

h=-t^2+3t+10

0 = - t^2+3t+10

reversing sides:

t^2 - 3t - 10 = 0

By completing the squares or factoring, we can get the roots:

(t-5) (t+2) = 0

t=5 or t=-2

Since time cannot be negative, therefore:

t = 5 seconds

Answer is D.