1) a projectile is thrown upward so that its distance above the ground after t seconds is
h=-10t2 +440 t. after how many seconds does it reach its maximum height?

After 22 seconds the projectile reach its maximum height of 4,840 units

Step-by-step explanation:

we have

This is a vertical parabola downward (because the leading coefficient is negative)

The vertex is a maximum

Find out the coordinates of the vertex

Convert the quadratic equation in vertex form

Factor -10

Complete the square

Rewrite as perfect squares

The vertex is the point (22,4,840)

therefore

After 22 seconds the projectile reach its maximum height of 4,840 units

answer: $201

step-by-step explanation: to get the answer, you first get 3 nieces that he sold and multiply it by 67 and get $201, so he earned $201 selling his nieces.