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Brrunno [24]
2 years ago
7

1. Hoover Dam spans the Colorado

Mathematics
1 answer:
Alona [7]2 years ago
5 0

BEST estimate of this  amount is 2(10^{7}) . Correct option A. 2 x 10^7 .

<u>Step-by-step explanation:</u>

Here we have , Hoover Dam spans the Colorado  River on the Nevada-Arizona state  line. For its construction, the federal  government purchased 21,670,000  pounds of gates and valves. We need to find BEST estimate of this  amount . Let's find out:

21,670,000  pounds

⇒ 21,670,000  pounds

⇒ 21,670,000

⇒ 2167(10^{4})

⇒ 2.167(10^{3})(10^{4})

⇒ 2.167(10^{3+4})

⇒ 2.167(10^{7})

Now, Rounding of 2.167 we get 2  ,So

⇒ 2(10^{7})

Hence ,  BEST estimate of this  amount is 2(10^{7}) . Correct option A. 2 x 10^7 .

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HELP NEEDED, GIVING BRAINLIEST!
Nataly_w [17]

The correct answer is:

B. This is a dilation about (0, 0) with a scale factor of 4; A'(8, 4), B' (16, 4), C' (16, -12).

Step-by-step explanation:

Given

Dilation: D : (x,y) => (4x,4y)

And Vertices

A ( 2, 1 ), B ( 4, 1 ), C ( 4, -3 )

Applying dilation on all vertices

A ( 2, 1 ) => A'(4*2, 4*1) => A'(8,4)\\B ( 4, 1 ) = > B' (4*4 ,4*1) = > B'(16,4)\\C(4,-3) => C' (4*4 , 4*-3) => C'(16, -12)

To find the scale factor,

As we are multiplying each vertex coordinate by 4, the dilation factor is 4.

Moreover,

\frac{A'}{A} = \frac{(8,4)}{(2,1)} = (4,4)

Hence the scale factor is 4.

So,

The correct answer is:

B. This is a dilation about (0, 0) with a scale factor of 4; A'(8, 4), B' (16, 4), C' (16, -12).

Keywords: Dilation, Scale factor

Learn more about dilation at:

  • brainly.com/question/10435836
  • brainly.com/question/10541435

#LearnwithBrainly

4 0
3 years ago
Best known for its testing program, ACT, Inc., also compiles data on a variety of issues in education. In 2004 the company repor
GarryVolchara [31]

Answer:

\mu_p -\sigma_p = 0.74-0.0219=0.718

\mu_p +\sigma_p = 0.74+0.0219=0.762

68% of the rates are expected to be betwen 0.718 and 0.762

\mu_p -2*\sigma_p = 0.74-2*0.0219=0.696

\mu_p +2*\sigma_p = 0.74+2*0.0219=0.784

95% of the rates are expected to be betwen 0.696 and 0.784

\mu_p -3*\sigma_p = 0.74-3*0.0219=0.674

\mu_p +3*\sigma_p = 0.74+3*0.0219=0.806

99.7% of the rates are expected to be betwen 0.674 and 0.806

Step-by-step explanation:

Check for conditions

For this case in order to use the normal distribution for this case or the 68-95-99.7% rule we need to satisfy 3 conditions:

a) Independence : we assume that the random sample of 400 students each student is independent from the other.

b) 10% condition: We assume that the sample size on this case 400 is less than 10% of the real population size.

c) np= 400*0.74= 296>10

n(1-p) = 400*(1-0.74)=104>10

So then we have all the conditions satisfied.

Solution to the problem

For this case we know that the distribution for the population proportion is given by:

p \sim N(p, \sqrt{\frac{p(1-p)}{n}})

So then:

\mu_p = 0.74

\sigma_p =\sqrt{\frac{0.74(1-0.74)}{400}}=0.0219

The empirical rule, also referred to as the three-sigma rule or 68-95-99.7 rule, is a statistical rule which states that for a normal distribution, almost all data falls within three standard deviations (denoted by σ) of the mean (denoted by µ). Broken down, the empirical rule shows that 68% falls within the first standard deviation (µ ± σ), 95% within the first two standard deviations (µ ± 2σ), and 99.7% within the first three standard deviations (µ ± 3σ).

\mu_p -\sigma_p = 0.74-0.0219=0.718

\mu_p +\sigma_p = 0.74+0.0219=0.762

68% of the rates are expected to be betwen 0.718 and 0.762

\mu_p -2*\sigma_p = 0.74-2*0.0219=0.696

\mu_p +2*\sigma_p = 0.74+2*0.0219=0.784

95% of the rates are expected to be betwen 0.696 and 0.784

\mu_p -3*\sigma_p = 0.74-3*0.0219=0.674

\mu_p +3*\sigma_p = 0.74+3*0.0219=0.806

99.7% of the rates are expected to be betwen 0.674 and 0.806

5 0
3 years ago
Simplify -4 1/4-(-9 1/2) = ? <br><br>A. -13 1/3 <br>B. -5 1/4<br>C. 13 1/3<br>D. 5 1/4​
bagirrra123 [75]

Answer:

B

Step-by-step explanation:

Hope this helps

5 0
2 years ago
I’m really bad at math can someone help me?(this is due today!)
dangina [55]
Okay i believe the first one is 4/7 and the second one is 2. also don’t listen to them. sometimes it can be hard and you start to stress. good luck and if this isn’t right i’m so sorry :) keep your head up!!!
6 0
2 years ago
0.65 is 10 times as much as
leonid [27]
0.65 x 10 = 6.5
0.65 is 10 times as much as 6.5
3 0
3 years ago
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