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3 years ago

Which expression represents 3 less than four times a

Mathematics

2 answers:

ella [17]3 years ago

7 0

I hope this will help

gayaneshka [121]3 years ago

3 0

Answer:

4a - 3

Step-by-step explanation:

"four times a" = 4 * a = 4a

"3 less than" = -3

Combine the terms: 4a - 3

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3/4 divided by 5 1/5

olga2289 [7]

Answer:

15/104

Step-by-step explanation:

To divide fractions take the reciprocal (invert the fraction) of the divisor and multiply the dividend. This is the quickest technique for dividing fractions. The top and bottom are being multiplied by the same number and, since that number is the reciprocal of the bottom part, the bottom becomes one.

6 0

3 years ago

The National Institute of Standards and Technology (NIST) supplies "standard materials" whose physical properties are supposed t

Lady bird [3.3K]

Answer:

$10.08-1.64\frac{0.1}{\sqrt{6}}=10.013$

$10.08+1.64\frac{0.1}{\sqrt{6}}=10.147$

So on this case the 90% confidence interval would be given by (10.013;10.147)

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".

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

$\mu$ population mean (variable of interest)

$\sigma =0.1$ represent the population standard deviation

n represent the sample size

Solution to the problem

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

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

In order to calculate the mean and the sample deviation we can use the following formulas:

$\bar X= \sum_{i=1}^n \frac{x_i}{n}$ (2)

$s=\sqrt{\frac{\sum_{i=1}^n (x_i-\bar X)}{n-1}}$ (3)

The mean calculated for this case is $\bar X=10.08$

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 tabel to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that $z_{\alpha/2}=1.64$

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

$10.08-1.64\frac{0.1}{\sqrt{6}}=10.013$

$10.08+1.64\frac{0.1}{\sqrt{6}}=10.147$

So on this case the 90% confidence interval would be given by (10.013;10.147)

5 0

3 years ago

The cost of a product has been increasing each year. The graph shows data about the product’s cost over time.

ruslelena [56]

C. the price goes up $1 every year\

4 0

3 years ago

Read 2 more answers

Find the area of a trapezoid please help im so lost

Murrr4er [49]

Here, trapezoid is composed of two triangles, and one rectangle.
So, Area of rectangle = 4 * 7 = 28 cm²
Area of a triangle = 1/2 * 3 * 7 = 21/2 = 10.5 cm²

Area of Trapezoid = area of rectangle + 2(area of triangle)
= 28 + 2(10.5)
= 28 + 21 = 49

In short, Your Answer would be 49 cm²

Hope this helps!

5 0

3 years ago

At 2:00 PM a car's speedometer reads 30 mi/h. At 2:20 PM it reads 50 mi/h. Show that at some time between 2:00 and 2:20 the acce

storchak [24]

Answer:

The correct answer will be "60 min/hour".

Step-by-step explanation:

At time 2:00 PM

A car reads = 30 mi/h

At time 2:20 PM

A car reads = 50 mi/h

Now,