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.

Answers

Answer 1

Answer: $S = 704 \ m^2 \nwidth \ of \ the \ deck - x \n \nS=a \cdot b \n \n (10+2x)(20+2x) = 704 \n \n 200+20x +40x+4x^2-704 =0\n \n4x^2 +60x -504=0\ \ /:4$

$x^2+15x -126=0\n \na=1, \ b=15 , \ c= - 126 \n \n\Delta =b^2-4ac = 15^2 -4\cdot1\cdot (-126) = 225 +504=729 \n \nx_(1)=(-b-√(\Delta) )/(2a)=(-15-√(729))/(2 )=( -15-27)/(2)=(-42)/(2)=-21 \ can \ not\ be \ negative \n \nx_(2)=(-b+√(\Delta) )/(2a)=(-15+√(729))/(2 )=( -15+27)/(2)= 6 \ m \n \n Answer : \ waist \ width \ is \ 6 \ m$

Answer 2

Answer: 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)
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Can explain that question? please ?& answer

X=7y-9
X+7y=8

Need help using substitution. ?! Please

Answers

X=7y-9
X=-7y+8
7y-9=-7y+8
+9= +9
7y=-7y+17
+7y=+7y
14y=17
14y/14=17/14
Y=17/14

Is this right and what's the answer for number 3?

Answers

Answer: Hello!

the problems are wrong:

in the first problem, you have 38 rocks, and you can separate them into groups of 10 or in single rocks.

You have 4 options to do it:

0 groups of 10, and 38 single rocks.

1 group of ten and (38 - 19) = 28 single rocks

(this is 10 rocks in the group of then + 28 single rocks = 38 total rocks)

2 groups of ten and (38 - 2*10) = 18 single rocks

3 groups of ten and (38 - 3*10) = 8 single rocks

and you can't form more groups of tens because you only have 8 single rocks left at this point.

in the second problem, the case is the same, now you have 30 pieces of felt and you can divide them into groups of 10 or in single pieces.

then the possible options are:

0 groups of ten and 30 single pieces

1 group of ten and (30 - 10) = 20 single pieces

2 groups of ten and (30 - 2*10) = 10 single pieces

3 groups of ten and (30 - 3*10) = 0 single pieces

in the third problem you need to write, similarly as i did, why you organized the rocks or the pieces as you did.

That looks great! But say you chose number 2. You could say you organized it by multiplying single packs by the pieces of packs.

You are 5 feet tall and cast an 8-foot shadow. A lamppost nearby casts a shadow that is 20 feet. Which equation can you use to solve for the height (h) of

Answers

Answer:

Height of lamppost would is 12.5 feet.

Step-by-step explanation:

We are given a 5 feet tall boy form shadow with 8 foot.

As we know height is directly proportional to shadow length.

$\therefore h\propto s$

$h=ks$

where, h is height of boy, k is constant of proportionality and s is shadow length.

when h=5 , s=8

5=8k

$k=(5)/(8)$

We need to find height when shadow length is 20 feet.

$h=(5)/(8)* 20\Rightarrow 12.5\text{ foot}$

Thus, Height of lamppost would be 12.5 feet.

5 : 8 = x : 20
20*5 = 8x
x = 12,5
Therefore height of the lamp is 12.5 feet :)

Madison loves her stuffed dolphin toy. The toy is 27 inches long. If her brother came and sliced the dolphin in half what would the size of the dolphin be?