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3 years ago

Please help!! Middle school math, this is timed!! No links or i will report!

Mathematics

2 answers:

charle [14.2K]3 years ago

7 0

Answer:

95 dollars

Step-by-step explanation:

the only question is 48 plus 37......

Lelechka [254]3 years ago

5 0

It’s an addition problem

48 + 37

85

Aiden earned $85 in total

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What is the simplified form of each expression? a. (6 + 3)2 − 4 b. 23 + (14 − 4) ÷ 2

liraira [26]

Answer:

a. 14

b. 28

Step-by-step explanation:

a. ex: (6+3)2 - 4 = 9(2) - 4

18 - 4 = 14

b. ex: 23 + (14 - 4) / 2

Use PEMDAS

P 1st

D over A

28

Hope this helps!

5 0

3 years ago

yesterday Bethany sent 60 text messages she said that 50% of those messages were to her best friend how many text messages did B

DanielleElmas [232]

50% of 60 is 30 so 30 messages.

6 0

4 years ago

Read 2 more answers

(6) (Bonus) Determine the Cartesian equation of the surface with spherical coordinate equation rho = 2 cos θ sin φ − 2 sin θ sin

KonstantinChe [14]

Answer:

Hence, the sphere has a radius of $\sqrt{3}$ and is centered at the point (1,-1,1)

Step-by-step explanation:

We have the equation

$\rho=2cos\theta cos\phi-2sin\theta sin\phi+2cos\phi$

We have to take into account the relation between coordinates

$\rho=\sqrt{x^2+y^2+z^2}\\x=\rho cos\theta sin\phi\\y=\rho sin\theta sin\phi\\z= \rho cos\phi$

by substituting we have:

$\rho=2[\frac{x}{\rho}-\frac{y}{\rho}+\frac{z}{\rho}]\\\\\rho^2=2x-2y+2z\\\\x^2+y^2+z^2=2x-2y+2z$

We have to complete squares:

$(x^2-2x+1)+(y^2+2y+1)+(z^2-2z+1)-1-1-1=0\\\\(x-1)^2+(y+1)^2+(z-1)^2=3$

Hence, the sphere has a radius of $\sqrt{3}$ and is centered at the point (1,-1,1)

hope this helps!!

4 0

3 years ago

A cocktail nut mix should have the following minimum requirements in a can of 1 pound being sold at $3.99 a can at retail stores

Misha Larkins [42]

Answer:

Nut

Step-by-step explanation:

6 0

3 years ago

The mean weight of 10 randomly selected newborn babies at a local hospital is 7.14 lbs and the standard deviation is 0.87 lbs. A

sergejj [24]

Answer:

a) $ME= 1.83 \frac{0.87}{\sqrt{10}}=0.5035$

b) 90% of all samples of size 10 have sample means within 0.5035 of the population mean.

c) The 90% confidence interval would be given by (6.636;7.643)

d) Yes, since the lower limit for the 90% confidence interval is higher than the value of 6.5 we can conclude that the true mean is significantly higher than 6.5 at 10% of significance. (6.636>6.5)

e) If we increase the confidence level that implies increase the margin of error. Since with more confidence level the value for the critical value $t_{\alpha/2}$ increase. So then the new interval would be wider than the original.

Step-by-step explanation:

Previous concepts

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".

$\bar X=7.14$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s=0.87 represent the sample standard deviation

n=10 represent the sample size

Part a

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

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

And the margin of error is given by:

$ME= t_{\alpha/2}\frac{s}{\sqrt{n}}$

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=10-1=9$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.05,9)".And we see that $t_{\alpha/2}=1.83$

$ME= 1.83 \frac{0.87}{\sqrt{10}}=0.5035$

Part b

90% of all samples of size 10 have sample means within 0.5035 of the population mean.

Part c

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

$7.14-1.83\frac{0.87}{\sqrt{10}}=6.637$

$7.14+1.83\frac{0.87}{\sqrt{10}}=7.643$

So on this case the 90% confidence interval would be given by (6.636;7.643)

Part d

Yes, since the lower limit for the 90% confidence interval is higher than the value of 6.5 we can conclude that the true mean is significantly higher than 6.5 at 10% of significance. (6.636>6.5)

Part e

If we increase the confidence level that implies increase the margin of error. Since with more confidence level the value for the critical value $t_{\alpha/2}$ increase. So then the new interval would be wider than the original.

7 0

4 years ago