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Oduvanchick [21]
3 years ago
8

The radius of one sphere measures twice the length of another. The ratio of their surface areas is

Mathematics
2 answers:
Katena32 [7]3 years ago
6 0

Answer:

4:1

Step-by-step explanation:

Alex787 [66]3 years ago
4 0
4:1
Because the ratio of areas is the ratio of the radii (or diameters) squared.
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Pls help me with my homework I need help
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Solve the inequality 9/2 + v > 7/5
statuscvo [17]

Answer:

the answer is -31/20

Step-by-step explanation:

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2 years ago
A Statistics professor has observed that for several years students score an average of 106 points out of 150 on the semester ex
tekilochka [14]

Answer:

Step-by-step explanation:

We would set up the hypothesis test. This is a test of a single population mean since we are dealing with mean

For the null hypothesis,

µ = 106

For the alternative hypothesis,

µ > 106

It is a right tailed test because of >.

Since no population standard deviation is given, the distribution is a student's t.

Since n = 241,

Degrees of freedom, df = n - 1 = 241 - 1 = 240

t = (x - µ)/(s/√n)

Where

x = sample mean = 109

µ = population mean = 106

s = samples standard deviation = 8.3

a) test statistic, t = (109 - 106)/(8.3/√241) = 5.61

We would determine the p value using the t test calculator. It becomes

p = 0.00001

Since alpha, 0.05 > than the p value, 0.00001, then we would reject the null hypothesis. Therefore, At a 5% level of significance, this improvement seem to be practically​significant.

b) Confidence interval is written in the form,

(Sample mean - margin of error, sample mean + margin of error)

The sample mean, x is the point estimate for the population mean.

Margin of error = z × s/√n

Where

s = sample standard deviation

n = number of samples

From the information given, the population standard deviation is unknown, hence, we would use the t distribution to find the z score

df = 240

Since confidence level = 95% = 0.95, α = 1 - CL = 1 – 0.95 = 0.05

α/2 = 0.05/2 = 0.025

the area to the right of z0.025 is 0.025 and the area to the left of z0.025 is 1 - 0.025 = 0.975

Looking at the t distribution table,

z = 1.6512

Margin of error = 1.6512 × 8.3/√241

= 0.88

Confidence interval = 109 ± 0.88

7 0
3 years ago
A parachute speed during a free fall reaches117 miles per hour What is the speed in feet per second At the speed how many feet w
qwelly [4]

Answer:

Speed is 171.6 ft/s and distance is 1716 feet

Step-by-step explanation:

Given that,

The speed of a parachute = 117 miles per hour.

1 mph = 1.47 ft/s

117 mph = 171.6 ft/s

We need to find the distance it travel during 10 s. We know that the distance covered is equal to the product of speed and time taken. So,

d = vt

d=171.6\ ft/s\times 10\ s\\\\=1716\ \text{feet}

Hence, this is the required solution.

3 0
2 years ago
Solve for x: 3(x + 1) = −2(x − 1) − 4<br><br> 1<br><br> −1<br><br> −5<br><br> −25
LekaFEV [45]

Answer:

x = - 1

Step-by-step explanation:

3(x + 1) = - 2(x - 1) - 4 ←  distribute parenthesis on both sides

3x + 3 = - 2x + 2 - 4

3x + 3 = - 2x - 2 ( add 2x to both sides )

5x + 3 = - 2 ( subtract 3 from both sides )

5x = - 5 ( divide both sides by 5 )

x = - 1

7 0
2 years ago
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