Question

A boat fires an emergency flare that travels upward at an initial velocity of 25 meters per second. To find the height in meters, h, of the flare at t seconds, use the function h= -5t^2 + 25t. After how many seconds will the flare be at a height of 10 meters?

Answer 1

So they're looking for what value of t gives an h value of 10

Answer 2

So let h=10, and substitute it in:

10 = -5t^2 + 25t

Answer 3

Solve for t, which will be your answer in seconds

Answer 4

Note that this gives you a quadratic equation, so you can use the quadratic formula or any other methods you've learned to figure out what t can be