1)The marketing department of a local shoe company found that approximately600 pairs of running shoes are sold monthly when the price of each pair is$100. It was also observed that, for each $1 reduction in price, an additional 20 pairs of running shoes are sold monthly. What price should the shoe store charge for a pair of running shoes in order to maximize revenue?

2)Jim wants to build a rectangular parking lot along a busy street but only has2,100 feet of fencing available. If no fencing is required along the street, find the maximum area of the parking lot.

3)If a ball is thrown upward at39.2 meters per second from the top of a building that is30 meters high, the height of the ball can be modeled by S=30+39.2t4.9t2, where t is the number of seconds after the ball is thrown.

a)Find the t-coordinate and S-coordinate of the vertex of the graph of this quadratic function.

b)The t-coordinate of the vertex of the graph of this quadratic function is t =