Question

Jlvesh is analyzing the flight of a few of his model rockets with various equations. In each equation, h is

the height of the rocket in centimeters, and the rocket was fired from the ground at timet = 0, where t is

measured in seconds.

Jivesh also has a more powerful Model B rocket. For this rocket, he uses the equation h=-90t4 + 300t.

When is the height of the Model B rocket 250 centimeters? Round your answers to the nearest

hundredth.

After t =

seconds, the rocket will have reached a height of 250 centimeters.

Answer 1

After t = 1.67 seconds, the rocket will have reached a height of 250 centimeters.

Explanation:

Given

--- correct expression

Required: When does height = 250 cm

To do this, we have:

This gives:

Rewrite as:

Divide through by 10

Expand

Factorize:

This gives:

Solve for 3t

Solve for t