Quadratics word problems

1. A manufacturer has been selling light bulbs for $2.00 each. People have been buying 100 light bulbs per month. The manufacturer belives that for every $1.00 increase per bulb, 4 fewer bulbs will be sold each month. It costs the manufacturer $.50 to make each light bulb. Assume the manufacturer sells every light bulb that he makes and that any whole number of light bulbs can be made.
   1. What price should the manufacturer sell each light bulb to make the maximum profit each month?
   2. How many light bulbs will maximize the manufacturer’s monthly profit?
   3. What is the manufacturer’s monthly profit?
2. An object is moving in a straight line. It initially travels at a speed of 9 meters per second, and it speeds up at a constant rate of 2 meters per second each second. Under such conditions, the distance d, in meters, that the object travels is given by the equation d = t² + 9t, where t is in seconds. According to this equation, how long will it take the object to travel 22 meters?
3. A chain store manager has been told by the main office that daily profit, P, is related to the number of clerks working that day, X,according to the equation P = 300x – 25x².  What number of clerks will maximize the profit, and what is the maximum possible profit?