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2 years ago

Working alone, Darryl can mop a warehouse in 11 hours. Elisa can mop the same warehouse in 9

Mathematics

1 answer:

Harrizon [31]2 years ago

3 0

Answer:

≈ 5 hours

Step-by-step explanation:

Time needed if they work together:

1 / (1/11 + 1/9) =
1/ (20 / 99) =
99/20 ≈ 5 hours

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Can someone help with this math question

Tcecarenko [31]

Based on corresponding angles, the upper left angle will be the supplement of 130, which is 50 degrees. The upper right angle is perpendicular, so it is 90 degrees. Since the sum of all internal angles of a triangle is 180, the remaining angle (lower angle) is 40 degrees. This is choice G.

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2 years ago

What is the value of fraction 1 over 2x3 + 5.3y, when x = 2 and y = 3?

NikAS [45]

Hello, let's figure this one out together.

Me, myself had to write this down in the notes form to understand what I was doing.

In the fraction, multiply the 2's by 3.

1 over 2(2^3)+5.3(3)

1 over 2(2^3)+(5.3)(3)

Simplify each by step.

You end of up with a decimal.

You have a total of 0.031348.

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3 years ago

Quanto fica 8.000 reais em dólares ?

Gelneren [198K]

It is 2.47 dollars in the united states

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3 years ago

A random sample of 50 recent college graduates results in a mean time to graduate of 4.58 years, with a standard deviation of 1.

Anna007 [38]

Answer:

The 90% confidence interval for the mean time to graduate with a bachelor’s degree is (4.32, 4.84).

Yes, this confidence interval contradict the belief that it takes 4 years to complete a bachelor’s degree.

Step-by-step explanation:

The (1 - α)% confidence interval for population mean μ, when the population standard deviation is not known is:

$CI=\bar x\pm t_{\alpha/2, (n-1)}\times \frac{s}{\sqrt{n}}$

The information provided is:

$\bar x=4.58\\s=1.10\\\alpha =0.10$

Compute the critical value of t for 90% confidence interval and (n - 1) degrees of freedom as follows:

$t_{\alpha/2, (n-1)}=t_{0.10/2, (50-1)}=t_{0.05, 49}=1.671$

*Use a t-table for the probability.

Compute the 90% confidence interval for population mean μ as follows:

$CI=\bar x\pm t_{\alpha/2, (n-1)}\times \frac{s}{\sqrt{n}}$

$=4.58\pm 1.671\times \frac{1.10}{\sqrt{50}}\\=4.58\pm 0.26\\=(4.32, 4.84)$

Thus, the 90% confidence interval for the mean time to graduate with a bachelor’s degree is (4.32, 4.84).

If a hypothesis test is conducted to determine whether it takes 4 years to complete a bachelor’s degree or not, the hypothesis will be:

Hₐ: The mean time it takes to complete a bachelor’s degree is 4 years, i.e. μ = 4.

Hₐ: The mean time it takes to complete a bachelor’s degree is different from 4 years, i.e. μ ≠ 4.

The decision rule based on a confidence interval will be:

Reject the null hypothesis if the null value is not included in the interval.

The 90% confidence interval for the mean time to graduate with a bachelor’s degree is (4.32 years, 4.84 years).

The null value, i.e. μ = 4 is not included in the interval.

The null hypothesis will be rejected at 10% level of significance.

Thus, it can be concluded that that time it takes to complete a bachelor’s degree is different from 4 years.

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3 years ago

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Answer:

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