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3 years ago

I need the answer please

Mathematics

2 answers:

Allushta [10]3 years ago

7 0

Step-by-step explanation:

So, it is a question of Arithmetic Progression.

Answer attached...

Hope it helps :)

photoshop1234 [79]3 years ago

4 0

It would first be 0.7 and then 1.1

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I don’t understand what to solve.

White raven [17]

Well since it gives you 2 gas stations it wants you to compare prices

Als gas station will be A
At-one will be B

since station A has $3.259/ gallon I assume
and B has $3.199/ gallon

just subtract them

so 3.259 -3.199 = 0.06

gas is less at station B noticeably costs less so thats your first answer

for the next one if you bought gallon of gas at the cheaper station you'd be saving $0.06/gallon since we got the difference from subtracting them.

3 0

3 years ago

How dose north america achieve 480VAC with 3 pole 120VAC

makvit [3.9K]

Answer:

There are a variety of factors driving the

adoption of 415/240VAC distribution. First,

distributing at these increased voltages

enables overall efficiency to be enhanced

by eliminating the need for a voltage

transformation along the power path. For

example, in a 415V system, the L-N voltage

is 240V, which is compatible with most all IT

loads. By shifting the UPS output distribution

voltage to 415/240 V three-phase (L-L/

L-N), most of the existing servers today can

be powered with 240V single-phase (L-N)

without any intermediate transformation.

Removing the need for a transformer

streamlines the power path and can increase

efficiency approximately 1.5 percent.

The adoption of a 415/240VAC distribution

model also can yield additional savings at

the device-level in the form of increased

efficiency for server power supplies. As

previously mentioned, today’s power

supplies can handle a wide range of incoming

voltages. Based on the actual voltage being

fed into the power supply, efficiencies can

range from as low as 80 percent (at 100V

nominal) to as much as 94 percent (at 240V

nominal) across all manufacturers.

Furthermore, while the typical efficiency

differential between 240V and 208V gained

at the server power supply today is a relatively

minimal, only 0.3 percent across most of

the load range, the efficiency differential

between 240V and 120V servers can be as

much as 2 percent for a given power supply.

It is this value that often gets overstated by

some manufacturers when comparing 415V

distribution to “traditional methods,” as

there are relatively few servers or peripherals

installed today that are operating at 120V.

Step-by-step explanation:

7 0

3 years ago

The proprietor of a boutique in New York wanted to determine the average age of his customers. A random sample of 25 customers r

jolli1 [7]

Answer:

$28-2.064\frac{10}{\sqrt{25}}=23.872$

$28+2.064\frac{10}{\sqrt{25}}=32.128$

So on this case the 95% confidence interval would be given by (23.9;32.1)

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".

$\bar X=28$ represent the sample mean

$\mu$ population mean (variable of interest)

s=10 represent the sample standard deviation

n=25 represent the sample size

Solution to the problem

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

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

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

$df=n-1=25-1=24$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ 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(0.025,24)".And we see that $t_{\alpha/2}=2.064$