Answered

Get the information you need with the help of IDNLearn.com's expert community. Our platform is designed to provide reliable and thorough answers to all your questions, no matter the topic.

A swimming pool  20 m long and 10 m wide is surrounded by a deck of uniform width. The total area of the swimming pool and the deck is 704 m^2. Find the width of the deck.

Sagot :

Let x = width of the deck.
Therefore total area of pool : 
(10+2x)m*(20+2x)m = 704 m^2
( 200 + 20x + 40x + 4x^2 ) m^2 = 704 m^2
(200 + 60x + 4x^2)   = 704
 4x^2 + 60x = 704-200
 4x^2 + 60x = 504
 4x^2 + 60x - 504 = 0
4(x^2 + 15x - 126) = 0
(x+21) * (x-6) = 0
Therefore x, the deck's width is 6m (it can't be -21 as width is measured as a positive value)
Kindly press the Thank You button and indicate this as best answer if it answers your question correctly. Thanks.
Lilithidn
[tex]S = 704 \ m^2 \\width \ of \ the \ deck - x \\ \\S=a \cdot b \\ \\ (10+2x)(20+2x) = 704 \\ \\ 200+20x +40x+4x^2-704 =0\\ \\4x^2 +60x -504=0\ \ /:4[/tex]
 
[tex]x^2+15x -126=0\\ \\a=1, \ b=15 , \ c= - 126 \\ \\\Delta =b^2-4ac = 15^2 -4\cdot1\cdot (-126) = 225 +504=729 \\ \\x_{1}=\frac{-b-\sqrt{\Delta} }{2a}=\frac{-15-\sqrt{729}}{2 }=\frac{ -15-27}{2}=\frac{-42}{2}=-21 \ can \ not\ be \ negative \\ \\x_{2}=\frac{-b+\sqrt{\Delta} }{2a}=\frac{-15+\sqrt{729}}{2 }=\frac{ -15+27}{2}= 6 \ m \\ \\ Answer : \ waist \ width \ is \ 6 \ m[/tex]


View image Lilith
We appreciate your presence here. Keep sharing knowledge and helping others find the answers they need. This community is the perfect place to learn together. Your questions deserve reliable answers. Thanks for visiting IDNLearn.com, and see you again soon for more helpful information.