1.A manufacturer of aluminum doors currently is able to sell 400 doors per week at a price of $80 each. If the price were lowered to $75 each, an additional 50 doors per week could be sold. Estimate the current elasticity of demand for thedoors, and also estimate the current value of themanufacturer's marginal-revenue function.

The elasticity of demand for the doors is approximately =

(put an integer or a decimal. Do not round until the final answer. Then round to the nearest hundredth asneeded.)

2.Sociologists studied the relation between income and number of years of education for members of a particular urban group. They found that a person with x years of education before seeking regular employment can expect to receive an average yearly income of y dollars per year. This is represented by the function y=5x5/2+4700 for 4x16. Find the rate of change of income with respect to number of years of education. Evaluate the expression when x=11.

What is the rate of change of income with respect to number of years ofeducation?

dy/dx=. (simplify your answer)

3.For the equationsbelow, q is the total number of units produced per day by m employees of amanufacturer, and p is the price per unit at which the q units are sold. Find themarginal-revenue product for the given value of m.

q=400mm2/40, p=0.9q+20; m=30

Themarginal-revenue product when m=30 is =

. (Type an integer or adecimal.)

4.Find the indicated marginal cost at the given production level.

c=7x+0.9y2+6y+750; c/y, x=60, y=40

The marginal cost is $=

.

(Simplify your answer. Use integers or decimals for any numbers in theexpression.)

note for number 4 that 0.9y2 the 2 is a square ( don't know how to make the 2 a square on my laptop)

.