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2 years ago

I’ll mark y brainlist for the correct answer!

Mathematics

2 answers:

inna [77]2 years ago

5 0

Answer:

16 / C

Step-by-step explanation:

-4 x -4 = 16

4 x 4 = 16

two negatives cancel out when multiplying, that is why it equals 16*

Lady_Fox [76]2 years ago

3 0

Answer:

Step-by-step explanation:

4×4=16

-4×-4=16

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What is distributive property and one example of it?

mestny [16]

Example of distributive property: 4(2+3)
The first step is to multiply the 4 and the 2
It will now look like 8+4(3)
Now you must multiply the 4 and the 3
Then it will look like 8+12
In which 8+12=20

6 0

2 years ago

Help please!!! There’s a picture

ruslelena [56]

Answer:

4/5 and 5/2

Step-by-step explanation:

took it

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1 year ago

A wind turbine is located at the top of a hill where the wind blows steadily at 12 m/s, and stands 37 m tall. The air then exits

marta [7]

Answer:

Power generated = 4.315 kW

Step-by-step explanation:

Given,

speed of wind when enters into the turbine, V = 12 m/s

speed of wind when exits from the turbine, U = 9 m/s

mass flow rate of the wind, m = 137 kg/s

According to the law of conservation of energy

Energy generated = change in kinetic energy

Since, the air is exiting at same elevation. So, we will consider only kinetic energy.

Energy generated in one second will be given by,

$E\ =\ \dfrac{1}{2}.mV^2-\dfrac{1}{2}.m.U^2$

$=\ \dfrac{1}{2}\times 137\times (12)^2-\dfrac{1}{2}\times 137\times (9)^2$

=4315.5 J

= 4.315 kJ

So, energy is generated in one second = 4.315 kJ

Power generated can be given by,

$P\ =\ \dfrac{\textrm{energy generated}}{time}$

And the energy is generated is already in per second so power generated will be 4.315 kW.

8 0

2 years ago

Find the height of a square pyramid that has a volume of 12 cubic feet and a base length of 3 feet.

kari74 [83]

<span>square pyramid</span>
V=b² h/3------------ >12=9*h/3------------ >h=12/3---- >h=4

the answer is h=4 feet

4 0

2 years ago

Read 2 more answers

Working for a car company, you have been assigned to find the average miles per gallon (mpg) for acertain model of car. you take

Orlov [11]

Answer:

a) The 95% confidence interval for the mean mpg, for the certain model of car is (23.3, 30.1). This means that we are 95% sure that the true mean mpg of the model of the car is between 23.3 mpg and 30.1 mpg.

b) Increasing the confidence level, the value of T would increase, thus increasing the margin of error and making the interval wider.

c) 37 cars would have to be sampled.

Step-by-step explanation:

Question a:

We have the sample standard deviation, and thus, the t-distribution is used to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 15 - 1 = 14

95% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 14 degrees of freedom(y-axis) and a confidence level of $1 - \frac{1 - 0.95}{2} = 0.975$ . So we have T = 2.1448

The margin of error is:

$M = T\frac{s}{\sqrt{n}} = 2.1448\frac{6.2}{\sqrt{15}} = 3.4$

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 26.7 - 3.4 = 23.3 mpg.

The upper end of the interval is the sample mean added to M. So it is 26.7 + 3.4 = 30.1 mpg.

The 95% confidence interval for the mean mpg, for the certain model of car is (23.3, 30.1). This means that we are 95% sure that the true mean mpg of the model of the car is between 23.3 mpg and 30.1 mpg.

b. What would happen to the interval if you increased the confidence level from 95% to 99%? Explain

Increasing the confidence level, the value of T would increase, thus increasing the margin of error and making the interval wider.

c. The lead engineer is not happy with the interval you constructed and would like to keep the width of the whole interval to be less than 4 mpg wide. How many cars would you have to sample to create the interval the engineer is requesting?

Width is twice the margin of error, so a margin of error of 2 would be need. To solve this, we have to consider the population standard deviation as $\sigma = 6.2$ , and then use the z-distribution.