Cynthia Besch wants to buy a rug for a room that is 19 ft wide and 32 ft long. She wants to leave a uniform strip of floor around the rug. She can afford to buy 420 square feet of carpeting. What dimensions should the rug have?

Respuesta :

Answer:

The rug should be 15 ft wide and 28 ft long.

Step-by-step explanation:

I have attached a figure that represents the situation.

The the rug is [tex]l[/tex] by [tex]h[/tex], the width of the strip of floor is [tex]w[/tex].

We are told that Cynthia can only afford 420 square feet of carpeting; therefore, it must be that

[tex]l*h=420[/tex] (this says the area of the rug must be 420 square feet)

From the figure we see that

[tex]l= 32-2w[/tex]

[tex]h=19-2w[/tex]

Therefore,

[tex]l*h=420\\\\(32-2w)(19-2w)=420[/tex]

We expand this equation and get:

[tex]4w^2-102w+608=420\\\\4w^2-102w+188=0[/tex]

using the quadratic equation we get two solutions:

[tex]w=2\\w=23.5[/tex]

since the second solution, namely [tex]w=23.5[/tex], is larger than one of the dimensions of the room (is greater than 19 ft) it cannot be the width of the strip; therefore, we take [tex]w=2[/tex] to be our solution.

Now we find the dimensions of the rug:

[tex]l=32-2(2)=28\\\\h=19-2(2)=15[/tex]

The rug is 15 ft wide and 28 ft long.

Ver imagen Poltergeist