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3 years ago

charley is 10 years old than her sister andi in 4 years charley will be twice as old as andi what are the present age of each

Mathematics

2 answers:

RSB [31]3 years ago

7 0

Answer:

Step-by-step explanation:

andi +10 = charley

and in 4 years

2*andi = charley +4

2*andi -4 = charley

now since we have charley as the indepentdent on each equation

set those parts equal to each other

andi + 10 = 2*andi -4

and + 14 = 2*andi

14 = andi

so andi is 14

charley is 24

blsea [12.9K]3 years ago

7 0

In the present, Charley is 16 and Andi is 6.

Explanation: After 4 years Charley will be 20 and Andi will be 10.
Charley is 20 in the future Andi is 10. Therefore, Charley is in the “twice as old as Andi”category.

Answer: Charley is 16 and Andi is 6

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What is the solution (x,y) to the system of equations below <br><br> x + 9y = 3<br> y= 1/3 x + 7

Alex_Xolod [135]

Let's solve this by substitution.

y is given by the 2nd eqn as y = (1/3)x + 7. Subst. (1/3)x + 7 into the first eqn as a replacement for y: x + 9( (1/3)x + 7) = 3.

clear out fractions by mult. all 3 terms by 3: 3x + 9x + 63 = 3

Combine like terms: 12x = -60. Then x = -5

Find y by subst. -5 for x in the 2nd equation: y = (1/3)(-5) + 7

= -5/3 + 35/3 = 30/3 = 10.

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3 years ago

A composite figure is shown.

VikaD [51]

The surface area of the pyramid is 60 square feet

The surface area of the square prism is 480 square feet

The surface area of the cube is 180 square feet

The total surface area is 720 square feet

<h3>Area of Composite figures</h3>

From the question, we are to calculate the surface area of each part of the composite figure

For the cube

Surface area of a cube is given by

$S = 6l^{2}$

Where $l$ is the length of a side

But only have 5 surfaces of the cube are part of the composite figure

∴ Surface area of the cubic part of the figure = $5l^{2}$

From the given information,

$l = 6 \ feet$

∴ Surface area of the cubic part of the figure = 5 × 6²

Surface area of the cubic part of the figure= 180 square feet

For the square prism

The surface area of a square prism is given by the formula,

$S = 2l^{2} + 4lh$

Where $l$ is the length of the sides and

$h$ is the height

But the <u>square surfaces</u> are not part of the surface of the figure

∴ Surface area of the square prism in the figure = $2l^{2} + 4lh - 2l^{2}$

Surface area of the square prism in the figure = $4lh$

From the given information,

$l = 6 \ feet$

$h = 20 \ feet$

Thus,

Surface area of the square prism part of the figure = 4×6×20

Surface area of the square prism part of the figure = 480 square feet

For the pyramid

The pyramid is a square pyramid

The surface area of a square pyramid is given by

$S = l^{2} + 2l\sqrt{\frac{l^{2} }{4}+h ^{2} }$

Where $l$ is the base length

and $h$ is the height of the prism

But the <u>square base</u> is not part of the surface of the figure

∴ Surface area of the pyramid part of the figure = $l^{2} + 2l\sqrt{\frac{l^{2} }{4}+h^{2} }\ - ( l^{2})$

Surface area of the pyramid part of the figure = $2l\sqrt{\frac{l^{2} }{4}+h^{2} }$

From the given information,

$l = 6 \ feet$

$h = 4 \ feet$

∴ Surface area of the pyramid part of the figure = $2(6)\sqrt{\frac{6^{2} }{4}+4^{2} }$

= $12\sqrt{\frac{36 }{4}+16}$

= $12\sqrt{9+16 }$

= $12\sqrt{25}$

= 12 × 5

= 60 square feet

Hence, the surface area of the pyramid is 60 square feet

Thus,

The total surface area = 180 square feet + 480 square feet + 60 square feet

The total surface area = 720 square feet

Hence, the total surface area is 720 square feet

Learn more on Calculating area of composite figures here: brainly.com/question/13175744

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2 years ago

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Svetllana [295]

Answer:

x=-4

Step-by-step explanation:

When dealing with an undefined slope it is always written as x=___.

Then plug in the blank with the x in (x,y), so x=-4.

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charley is 10 years old than her sister andi in 4 years charley will be twice as old as andi what are the present age of each​

charley is 10 years old than her sister andi in 4 years charley will be twice as old as andi what are the present age of each