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3 years ago

You have $5.00 in quarters and dimes. You have a total of 41 coins. How many of the coins are quarters?

Mathematics

1 answer:

Dmitry_Shevchenko [17]3 years ago

8 0

One because if you put two then the would be 50 and thats over 41

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What is the value of m∠3 if m∠5=70° and m∠2=60°?

Roman55 [17]

Answer : 50

Explanation : All angles of a triangle add up to 180

7 0

3 years ago

The percentage of body fat of a random sample of 36 men aged 20 to 29 found a sample mean of 14.42. Find a 95% confidence interv

Rina8888 [55]

Answer:

$14.42-1.96\frac{6.95}{\sqrt{36}}=12.150$

$14.42+ 1.96\frac{6.95}{\sqrt{36}}=16.690$

So on this case the 95% confidence interval would be given by (12.150;16.690)

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".

$\bar X=14.42$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=6.95$ represent the population standard deviation

n=36 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)

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: "=-NORM.INV(0.025,0,1)".And we see that $z_{\alpha/2}=1.96$

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

$14.42-1.96\frac{6.95}{\sqrt{36}}=12.150$

$14.42+ 1.96\frac{6.95}{\sqrt{36}}=16.690$

So on this case the 95% confidence interval would be given by (12.150;16.690)

5 0

4 years ago

What is the vertex for the following quadratic? f(x)=2(x - 4)^2 -8

Ghella [55]

Answer:

vertex = (4, - 8 )

Step-by-step explanation:

The equation of a quadratic in vertex form is

f(x) = a(x - h)² + k

where (h, k) are the coordinates of the vertex and a is a multiplier

f(x) = (x - 4)² - 8 ← is in vertex form

with (h, k ) = (4, - 8 ) ← coordinates of vertex

6 0

3 years ago

Please help!!

Kryger [21]

Switch y=2x+7 to 2x-y=-7 then multiply that equation by 2 to cancel out the y's. that ends up as 4x-2y=-14 which then you get x=-24. then you substitute x into one of the original equations y= 2(-24)+7 which equals y=-41

5 0

3 years ago

Can the polynomial below be factored into a perfect square? If not, select the answer that best describes why not.

pickupchik [31]

Answer:

C. It cannot be factored into a perfect square.

Step-by-step explanation:

Take the square roots of all the numbers present (64, 49, 8) and you will find that 8, the constant, is not a perfect square.

8 0

3 years ago