Cynthia Besch wants to buy a rug for a room that is 29 ft wide and 30 ft long. She wants to leave a uniform strip of floor around the rug. She can afford to buy 756 square feet of carpeting. What dimension should the rug have?
Mathematics · High School · Tue Nov 03 2020
Answered on
Given :
Length = 30 ft
Width = 29 ft
Area of carpeting = 756 sq ft
Let the uniform strip around floor is of length = x ft
This x feet will be 2 times along the length and
2 times along the width of room.
So, length of rug = 30 -2× x
Width of rug = 29 -2 × x
It will be rectangular in shape.
Area of a rectangle = Length × width
756 = (30 - 2x )(29 -2x)
756 = 870 - 58x -60x + 4x²
4x² - 118x + 870 - 756 = 0
4x² - 118x + 114 = 0
Taking 2 common from above equation
2(2x² - 59x + 57) = 0
2x² - 59x + 57 = 0
Now, by middle-term split method :
2x² - 57x - 2x + 57 = 0
x(2x - 57) -1(2x-57) = 0
(x-1) (2x- 57) = 0
So, x = 1, 57/2
So, possible dimensions are:
For x = 1
Length = 30 - 2(1)
= 30 - 2
= 28 feet
And width = 29 - 2(1)
= 29 - 2
= 27 feet
For x = 57/2
Length = 30 -2(57/2)
= 30 - 57
= -27
Since, length cannot be in negative . So, only possible dimensions of the rug are 28 feet and 27 feet.