I need help with this khan academy question

Answer: principal value = $500 and rate of interest = 4%.

Step-by-step explanation:

Let P = Principal value, r= rate of interest, t= time.

Formula for simple interest:

Interest = P x r x t

Final amount = P+ interest

= P+Prt

= P(1+rt)

Simple interest amounts to $560 in 3 years.

⇒ 560=  P(1+3r)

[tex]\Rightarrow\ P=\dfrac{560}{1+3r}[/tex]                   (i)

Simple interest amounts to $600 in 5 years.

⇒ 600=  P(1+5r)

[tex]\Rightarrow\ P=\dfrac{600}{1+5r}[/tex]                   (ii)

From (i) and (ii) , we get

[tex]\dfrac{560}{1+3r}=\dfrac{600}{1+5r}\\\\\Rightarrow\ 560(1+5r)=600(1+3)\\\\\Rightarrow\ 560+2800r=600+1800r\\\\\Rightarrow\ 2800r-1800r=600-560\\\\\Rightarrow\ 1000r=40\\\\\Rightarrow\ r=\dfrac{40}{1000}\\\\\Rightarrow\ r= 0.04= 4\%[/tex]

Put r= 0.04 in (ii), we get

[tex]P=\dfrac{600}{1+5(0.04)}\\\\=\dfrac{600}{1+0.2}\\\\=\dfrac{600}{1.2}\\\\=500[/tex]

Hence, principal value = $500 and rate of interest = 4%.

Solution :

Let x, y, z be the dimensions of the rectangle.

Volume of the rectangle (V) = xyz

Given that the vertex should lie on ellipse [tex]$4x^2 + y^2+4z^2=4$[/tex] .......(i)

So here the volume xyz must be maximum with constraints above.

We solve this using Lagranches method with variable λ

Lagranches function is

[tex]$F : xyz + \lambda(4x^2+y^2+4z^2-4)=0$[/tex] .....(ii)

To find λ, [tex]$\frac{dF}{dx}=0; \frac{dF}{dy}=0;\frac{dF}{dz}=0$[/tex]

[tex]$\frac{dF}{dx}=0 \Rightarrow yz+\lambda(16x)=0 \Rightarrow \lambda = -\frac{yz}{16x}$[/tex] .............(iii)

[tex]$\frac{dF}{dy}=0 \Rightarrow xz+\lambda(2y)=0 \Rightarrow \lambda = -\frac{xz}{2y}$[/tex] ..................(iv)

[tex]$\frac{dF}{dz}=0 \Rightarrow xy+\lambda(16z)=0 \Rightarrow \lambda = -\frac{xy}{16z}$[/tex] ...............(v)

Equating (iii) and (iv)

[tex]$-\frac{yz}{16x}=-\frac{xz}{2y} \Rightarrow y^2=8x^2 \Rightarrow y = \sqrt8 x$[/tex] ...............(vi)

Equating (iii) and (v)

[tex]$-\frac{yz}{16x}=-\frac{xy}{16z} \Rightarrow z^2=x^2 \Rightarrow z = x$[/tex] ....................(vii)

Substitute (vi) and (vii) in (i),

From (i),

[tex]$4x^2 + (\sqrt8 x)^2+4x^2 = 4$[/tex]

[tex]$\Rightarrow 4x^2 +8x^2+4x^2 = 4 \Rightarrow x = \frac{1}{4}$[/tex]

From (vi),

[tex]$y = \sqrt8 x$[/tex]

[tex]$\Rightarrow y= \sqrt8 \times \frac{1}{4} \Rightarrow y =\frac{\sqrt8}{4}$[/tex]

[tex]$\Rightarrow y =\frac{\sqrt{2\times4}}{4} \Rightarrow y = \frac{1}{\sqrt2}$[/tex]

From (vii),

z = x

[tex]$z =\frac{1}{4}$[/tex]

Therefore, for maximum volume the dimensions of a rectangle box are

[tex]$x =\frac{1}{4} ; y = \frac{1}{\sqrt2} ; z =\frac{1}{4}$[/tex]

Answer: the scale factor is 1/2

And the missing side is 5.5

Step-by-step explanation:

The larger triangle is twice the smaller triangle

The scale factor is 1/2 and the length of the missings side is 5.5 after using the concept of the scale factor.

The ratio among comparable dimensions of an object and a model with that object is known as an exponent in algebra. The replica will be larger if the scale factor is a whole number. The duplicate will be lowered if the step size is a fraction.

It is given that:

The two rectangles are shown in the picture:

Part A what is the scale factor used when going from the larger rectangle to the smaller one?

The scale factor = 8/16 = 1/2

The length of the missings side = 1/2(11) = 5.5

Thus, the scale factor is 1/2 and the length of the missings side is 5.5 after using the concept of the scale factor.

Learn more about the scale factor here:

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Answer: After 10 weeks he will run out of money. The ratio is 25:1

Step-by-step explanation:

Answer:

Step-by-step 4explanation:

Answer:

15 is 9 because the ratio is 3:15 in 1 hour, so you multiply by 3(hours) and you get 9

Step-by-step explanation:

I apologise but I'm too rusty at the other questions to be able to answer them anywhere close to accurate D:

9514 1404 393

Answer:

  13. 3/15 = 1/5

  14. 1/5 (or 3 Bieber songs per hour)

  15. 9

Step-by-step explanation:

13. The requested ratio is ...

  (3 Bieber songs)/(15 total songs) = 3/15 = 1/5

__

14. 1/5 is the "unit rate" for the ratio in problem 13. Its units are "Bieber songs per song played."

(IMO, this "unit rate" is pointless. For the purpose of problem 15, the applicable "unit rate" is Bieber songs per hour. That is 3 songs per hour.)

__

15. At a rate of 3 Bieber songs per hour, in 3 hours one might expect ...

  (3 songs/hour)(3 hours) = 9 songs . . . . by Bieber

Answer:

Step-by-step explanation:

0 would represent the surface of the water

4 seguall

3

2

1 above water

0-surface of the water

-1 in the water

-2

-3

-4

Answer:

on the surface, because 0 represents sea level.

Step-by-step explanation:

Hope this helps and good luck :)

Answer:

He would make 300 dollars.

Step-by-step explanation:

15 x 5 = 75

75 x 4 = 300.

Answer:

answer is 300

Step-by-step explanation:

Because if your doing it for 1 day you would have to 15*5 which five you 75. Then you multiple that 75 with the 4 and give you 300 within the 4 days..

Hopes this help.

Answer:

the whole

Step-by-step explanation:

I believe that the answer B,D,and E

Answer:

A, D, and E (I think)

Step-by-step explanation:

I'm pretty sure those would be the right answers, sorry that this isn't much of an explanation lol

Answer:

1<x<4

Step-by-step explanation:

this helps me out a lot in my math class

Answer:

x=4 and thats your answer thanks for helping you but if using the z-score it's 0

Step-by-step explanation:

1<x<4

The options equivalent to the given fraction are:   -11 ÷ 4,  -11 ÷(- 4), [tex]\frac{-11}{4}[/tex] , [tex]\frac{11}{-4}[/tex]

[tex]-\frac{11}{4}[/tex] is an improper fraction. An improper fraction is a fraction in which the numerator is larger than the denominator.  [tex]\frac{-11}{4}[/tex] can also be written as -11 ÷ 4.

In order to determine the answers, take note of the following rules:

Using the above rules, the equivalent options are:  -11 ÷ 4,  -11 ÷(- 4), [tex]\frac{-11}{4}[/tex] , [tex]\frac{11}{-4}[/tex]

A similar question was answered here: https://brainly.com/question/15382096?referrer=searchResults

The first, second, fourth, and fifth options among all are equivalent to [tex]\frac{-11}{4}[/tex].

These all are forms of division.

The division is an arithmetic operation that involves splitting a quantity or number into equal parts or groups. It is the inverse operation of multiplication. In division, a number called the dividend is divided by another number called the divisor to obtain the quotient.

The dividend is the total quantity or number being divided, while the divisor is the number by which the dividend is divided. The result of the division is called the quotient, which represents the number of times the divisor can be subtracted from the dividend to achieve equal parts.

Hence, the first, second, fourth, and fifth options are correct.

Learn more about division here:

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Step-by-step explanation:

(1 point)

No, there isn't a more efficient way to solve this system.

Yes, a more efficient way is to multiply the first equation by 4, add to eliminate y, then solve for x.

Yes, a more efficient way is to multiply the first equation by −4, add to eliminate y, then solve for x.

Yes, a more efficient way is to multiply the first equation by −4, add to eliminate x, then solve for y.

Answer:

1,-4

Step-by-step explanation:

The vertex is always that little spot there at the tip of a nonlinear function.

The value of x will be;

⇒ x = 3.75

What is an expression?

Mathematical expression is defined as the collection of the numbers variables and functions by using operations like addition, subtraction, multiplication, and division.

Given that;

The expression is,

⇒ 5x - 12 + 3x + 30 = 48

Now,

Solve the expression for x as;

The expression is,

⇒ 5x - 12 + 3x + 30 = 48

⇒ 8x - 12 + 30 = 48

⇒ 8x + 18 = 48

Subtract 18 both side as,

⇒ 8x - 18 = 48 - 18

⇒ 8x = 30

Divide by 8 as;

⇒ x = 30/8

⇒ x = 3.75

Thus, The value of x will be;

⇒ x = 3.75

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Answer:

its D

Step-by-step explanation:

Answer:

y=20

Step-by-step explanation:

8x

8(2.5)

8×2=16

8×0.5=4

16+4=20

y=20 in this equation

Answer:

[tex]\frac{5}{14}[/tex]

Step-by-step explanation:

First subtract the two terms by setting the first term as a fraction.

3 * [tex]\frac{5}{5}[/tex] = [tex]\frac{15}{5}[/tex]

Then subtract the terms.

[tex]\frac{15}{5}[/tex][tex]-\frac{1}{5}[/tex] = [tex]\frac{14}{5}[/tex]

Finally, flip the numerator and the denominator.

Answer:

B

Step-by-step explanation:

Answer: B

Step-by-step explanation:

Answer:

When two triangles are similar, the reduced ratio of any two corresponding sides is called the scale factor of the similar triangles.

Step-by-step explanation:

Answer:

0)2.50 2)5.00 4)10.00 6)15.00

Step-by-step explanation:

Answer:

y=4/2m-3 OR y=2m-3

Step-by-step explanation:

Answer:A system of linear equations has no solution when the graphs are parallel. Infinite solutions. A system of linear equations has infinite solutions when the graphs are the exact same line.

Step-by-step explanation:

Answer:

Y-3/5x+2

Step-by-step explanation:

Answer:

15

Step-by-step explanation:

just cause

Answer:

107

Step-by-step explanation: