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Andrei [34K]
3 years ago
9

An advisor to the mayor of a large city wants to estimate, within 3 minutes, the mean travel time to work for all employees who

work within the city limits. He knows that the standard deviation for all travel times is 12.25 minutes. He also wants to achieve a 95% confidence interval. He will poll a random sample of city employees. At least how many employees should he poll?
Mathematics
1 answer:
Shkiper50 [21]3 years ago
8 0

Answer:

64

Step-by-step explanation:

Given that an advisor to the mayor of a large city wants to estimate, within 3 minutes, the mean travel time to work for all employees who work within the city limits.

Let X be the random variable denoting the time for employees to travel within city limit

Std dev of X = 12.25 minutes

For 95% confidence interval Z critical 1.96 is used because population std dev is known

Margin of error = 1.96*std error = 3 (given)

i.e. 1.96(\frac{12.25}{\sqrt{n} } )=3

where n is the desired sample size.

Simplify to get

\frac{24.01}{\sqrt{n} } =3\\n=64.053

Hence atleast 64 employees should he poll

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(Because -10 x^{0} =-10(1)=-10. Therefore, you have that the correct option is the option B.
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Hank brought 2.4 pounds of apples.each pund cost $1.89. How much did hank spend on his apples?
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3 years ago
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4 0
3 years ago
Bryan and Jadyn had barbeque potato chips and soda at a football party. Bryan ate 5 oz of chips and drank 1 cup of soda for a
MaRussiya [10]

Answer:

1 oz of chips has 120mg of sodium, while in 1 cup of soda there are 50mg of sodium.

Step-by-step explanation:

This question can be solved by a system of equations.

I am going to say that:

x is the number of mg of sodium in 1 oz of chips.

y is the number of mg of sodium in a cup of soda.

Bryan ate 5 oz of chips and drank 1 cup of soda for a total of 650 mg of sodium.

This means that:

5x + y = 650

Jadyn ate 1 oz of chips and drank 5 cups of soda for a total of 250 mg of sodium.

This means that:

x + 5y = 250

From the first equation:

y = 650 - 5x

Replacing in the second

x + 5(650 - 5x) = 250

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25x = 3000

x = \frac{3000}{25}

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1 oz of chips has 120mg of sodium, while in 1 cup of soda there are 50mg of sodium.

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3 years ago
How can these models be used to find the sum 1.8 + 1.56?
enyata [817]

Answer:

The sum of  1.8 and 1.56 is 3.36 according to the model

Sum of decimals

Given the expression  1.8 + 1.56

Using the partial sum method

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Regroup as whole and decimal number

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1.8 + 1.56 = 3.36

Hence the sum of  1.8 and 1.56 is 3.36 according to the model

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