4. When computer software programs sell for $20 each 300
people will buy them. For every $5 increase, 30 fewer
people will buy. What is the maximum revenue?

6. A projectile is shot straight up from a height of 6m with
initial velocity of 80 m/s. It's height is given by the
equation
h = 6 + 80t ­5t2
How much time will it take to reach it's max height?
What is that height?

8. What is the maximum rectangular area that can be
enclosed by 120 m of fencing if one side of the rectangle
is an existing wall?

10. What is the maximum rectangular area that can be
enclosed by 120 m of fencing if one side of the rectangle
is an existing wall?