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3 years ago

8

Please Help! A new dirt bike valued at $9000 loses 18% of its value each year. What is the initial price of the dirt bike? I don

't understand how to solve this problem so if someone could show me how it would mean a lot.

1 answer:

Lelechka [254]3 years ago

7 0

Answer:

The new dirt bike should cost $9000

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Please answer <br> 2x^2+7x+3=0

Korolek [52]

Answer:

x+-(1)/(2),-3

Step-by-step explanation:

Thank you:)

8 0

3 years ago

Suppose the method of tree ring dating gave the following dates A.D. for an archaeological excavation site. Please show your wor

natita [175]

Answer:

a) $\bar X=\frac{1245+1245+1321+1191+1295+1330+1239+1250+1228}{9}= 1260.444$

b) $s =\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}$

And if we replace we got:

$s = 45.580$

c) For this case since the sampel size is n=9 <30 we can use the t distribution in order to find the confidence interval.

d) $1260.444-2.306 \frac{45.580}{\sqrt{9}}= 1225.408$

$1260.444+2.306 \frac{45.580}{\sqrt{9}}= 1295.480$

Step-by-step explanation:

For this case we ave the following data:

1245 1245 1321 1191 1295 1330 1239 1250 1228

Part a

We can calculate the sample mean with the following formula:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

And if we replace we got:

$\bar X= \frac{1245+1245+1321+1191+1295+1330+1239+1250+1228}{9}= 1260.444$

Part b

For this case we can use the following formula in order to find the sample standard deviation:

$s =\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}$

And if we replace we got:

$s = 45.580$

Part c

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

For this case since the sampel size is n=9 <30 we can use the t distribution in order to find the confidence interval.

Part d

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

We need to find the degrees of freedom given by:

$df = n-1 = 9-1=8$

Since the Confidence is 0.95 or 95%, the value of $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,8)".And we see that $t_{\alpha/2}=2.306$

Now we have everything in order to replace into formula (1):

$1260.444-2.306 \frac{45.580}{\sqrt{9}}= 1225.408$

$1260.444+2.306 \frac{45.580}{\sqrt{9}}= 1295.480$

8 0

4 years ago

Rewrite the expression below.<br><br> -2a( a + b - 5)+ 3 (-5a + 2b) +b (6a + b - 8)

Paul [167]

Answer:

b^2 + 4 a b - 2 b - 2 a^2 + -5 a

Step-by-step explanation:

Simplify the following:

-2 a (a + b - 5) + 3 (2 b - 5 a) + b (6 a + b - 8)

-2 a (-5 + a + b) = 10 a - 2 a^2 - 2 a b:

10 a - 2 a^2 - 2 a b + 3 (2 b - 5 a) + b (6 a + b - 8)

3 (2 b - 5 a) = 6 b - 15 a:

10 a - 2 a^2 - 2 a b + 6 b - 15 a + b (6 a + b - 8)

b (-8 + 6 a + b) = -8 b + 6 a b + b^2:

10 a - 2 a^2 - 2 a b - 15 a + 6 b + -8 b + 6 a b + b^2

Grouping like terms, 10 a - 2 a^2 - 2 a b - 15 a + 6 b - 8 b + 6 a b + b^2 = b^2 + (6 a b - 2 a b) + (6 b - 8 b) - 2 a^2 + (10 a - 15 a):

b^2 + (6 a b - 2 a b) + (6 b - 8 b) - 2 a^2 + (10 a - 15 a)

a b 6 + a b (-2) = 4 a b:

b^2 + 4 a b + (6 b - 8 b) - 2 a^2 + (10 a - 15 a)

6 b - 8 b = -2 b:

b^2 + 4 a b + -2 b - 2 a^2 + (10 a - 15 a)

10 a - 15 a = -5 a:

Answer: b^2 + 4 a b - 2 b - 2 a^2 + -5 a

8 0

3 years ago

What is the ratio equivalent to 0.l

NeTakaya

1 / 10 is the easiest answer. Remember ratios are just percentages. It could also be 2/20, 3/30, as long as it is 10%.

7 0

3 years ago

How do you find the slope of a line perpendicular to a given line?

enyata [817]

You have a line:
y=mx+b (slope-intercepted form)
m=slope of this line.

The slope of a line perpendicular to that given line will be: ´"m´"
m´=-1/m.

For example:
y=8x+3
m=8

The solpe fo a line perpendicular to "y=8x+3" is:
m`=-1/8

5 0

3 years ago