Question

The amount of paint needed to cover the calls of a room varies jointly as the perimeter of the room and the height of the wall. If a room with a perimeter of 60 feet and 8-foot walls requires 4.8 quarts of paint, find the amount of paint needed to cover the walls of a room with a perimeter of 65 feet and 10-foot walls.

Answer 1

Wall Area room 1 = 60 * 8
Wall Area room 2 = 65 * 10
so
4.8 ( 65*10 / 60*8)

Answer 2

A rectangular box with volume 490 cubic feet is built with a square base and top. The cost if $1.50 per square foot for the top and bottom and $2.00 per square foot for the sides. Let x represent the length of a side of the base. Express the cost of the box as a function of x.

Answer 3

height = 490/x^2
cost = 1.50*2x^2+ 2.00*490/x^2

Answer 4

suppose that the manufacturer of a gas clothes dryer has found that, when the unit price is p dollars, the revenue R(in dollars) is R(p)= -9p^2 +18,000p
What unit price should be established for the dryer to maximize revenue? What is the maximum revenue?