Question 313989: A rectangular pool is 30 feet wide and 40 feet long. It is surrounded on all four sides by a wooden deck that is x feet wide. The total area enclosed within the perimeter of the deck is 3000ft^2. What is the width of the deck?
Answer by checkley77(12844)   (Show Source):
You can put this solution on YOUR website! (30+2x)(40+2x)=3,000
1,200+80x+60x+4x^2=3,000
4x^2+140x+1,200-3,000=0
4x^2+140x-1800=0
(2x-20)(2x+90)=0
2x-20=0
2x=20
x=20/2
x=10 ft. ans. for the width of the wooden deck.
Proof:
(30+2*10)(40+2*10)=3,000
(30+20)(40+20)=3,000
50*60= 3,000
3,000=3,000
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