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2 years ago

Henry buy a machine on January at a cost of 24,000 The machine is deprecated using the double declined method The

Mathematics

1 answer:

77julia77 [94]2 years ago

5 0

Answer:

12000

Step-by-step explanation:

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The table shows the value of an account x years after the account was opened. Based on the exponential regression model, which i

lana66690 [7]

Answer:

Correct choice is B

Step-by-step explanation:

The exponential regression model can be written as exponential function

$y=a\cdot b^x.$

Then

$5,000=a\cdot b^0=a,\\ \\5,510=a\cdot b^2\Rightarrow 5,510=5,000\cdot b^2,\\ \\b^2=\dfrac{5,510}{5,000}=\dfrac{551}{500}\Rightarrow b\approx 1.05.$

Thus,

$y=5,000\cdot (1.05)^x.$

When $x=12,$ you get

$y(12)=5,000\cdot (1.05)^{12}\approx \$8,980.$

6 0

2 years ago

Read 2 more answers

BC= 12, AB= x-8, and AC= 2x-6. Find x

Lorico [155]

x=10, AC=14, AB=2, BC=12

3 0

2 years ago

A circle has an area of 9. What is the circumference?

Len [333]

The circumference of the circle is 10.36

7 0

2 years ago

Suppose that W1, W2, and W3 are independent uniform random variables with the following distributions: Wi ~ Uni(0,10*i). What is

nadya68 [22]

I'll leave the computation via R to you. The $W_i$ are distributed uniformly on the intervals $[0,10i]$ , so that

$f_{W_i}(w)=\begin{cases}\dfrac1{10i}&\text{for }0\le w\le10i\\\\0&\text{otherwise}\end{cases}$

each with mean/expectation

$E[W_i]=\displaystyle\int_{-\infty}^\infty wf_{W_i}(w)\,\mathrm dw=\int_0^{10i}\frac w{10i}\,\mathrm dw=5i$

and variance

$\mathrm{Var}[W_i]=E[(W_i-E[W_i])^2]=E[{W_i}^2]-E[W_i]^2$

We have

$E[{W_i}^2]=\displaystyle\int_{-\infty}^\infty w^2f_{W_i}(w)\,\mathrm dw=\int_0^{10i}\frac{w^2}{10i}\,\mathrm dw=\frac{100i^2}3$

so that

$\mathrm{Var}[W_i]=\dfrac{25i^2}3$

Now,

$E[W_1+W_2+W_3]=E[W_1]+E[W_2]+E[W_3]=5+10+15=30$

and

$\mathrm{Var}[W_1+W_2+W_3]=E\left[\big((W_1+W_2+W_3)-E[W_1+W_2+W_3]\big)^2\right]$

$\mathrm{Var}[W_1+W_2+W_3]=E[(W_1+W_2+W_3)^2]-E[W_1+W_2+W_3]^2$

We have

$(W_1+W_2+W_3)^2={W_1}^2+{W_2}^2+{W_3}^2+2(W_1W_2+W_1W_3+W_2W_3)$

$E[(W_1+W_2+W_3)^2]$

$=E[{W_1}^2]+E[{W_2}^2]+E[{W_3}^2]+2(E[W_1]E[W_2]+E[W_1]E[W_3]+E[W_2]E[W_3])$

because $W_i$ and $W_j$ are independent when $i\neq j$ , and so

$E[(W_1+W_2+W_3)^2]=\dfrac{100}3+\dfrac{400}3+300+2(50+75+150)=\dfrac{3050}3$

giving a variance of

$\mathrm{Var}[W_1+W_2+W_3]=\dfrac{3050}3-30^2=\dfrac{350}3$

and so the standard deviation is $\sqrt{\dfrac{350}3}\approx\boxed{116.67}$

# # #

A faster way, assuming you know the variance of a linear combination of independent random variables, is to compute

$\mathrm{Var}[W_1+W_2+W_3]$

$=\mathrm{Var}[W_1]+\mathrm{Var}[W_2]+\mathrm{Var}[W_3]+2(\mathrm{Cov}[W_1,W_2]+\mathrm{Cov}[W_1,W_3]+\mathrm{Cov}[W_2,W_3])$

and since the $W_i$ are independent, each covariance is 0. Then

$\mathrm{Var}[W_1+W_2+W_3]=\mathrm{Var}[W_1]+\mathrm{Var}[W_2]+\mathrm{Var}[W_3]$

$\mathrm{Var}[W_1+W_2+W_3]=\dfrac{25}3+\dfrac{100}3+75=\dfrac{350}3$

and take the square root to get the standard deviation.

8 0

2 years ago

Find the area of a circle with a

lina2011 [118]

Answer:

254.34 in.²

Step-by-step explanation:

area = πr²

given, radius = 9 cm

according to formula

→ 3.14 × (9)²

→ 3.14 × 81

→ 254.34 in.² ans.

hope this helps you !

6 0

2 years ago