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2 years ago

Work out 30 – 3 + 7 x 2

Mathematics

2 answers:

strojnjashka [21]2 years ago

7 0

The correct answer is 41

zhenek [66]2 years ago

5 0

30 - 3 + 7 x 2

30 - 3 + 14

27 + 14

41

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Sara is a drummer in her school is marching band she wants to make a geometrically similar model of a snare drum for her stuffed

strojnjashka [21]

Answer:

Option B.

Step-by-step explanation:

Let the radius of the snare drum = r

and radius of the model = R

Ratio of the dimensions of the snare drum and the model = 1 : 4

So, $\frac{r}{R}=\frac{1}{4}$

Now as per question, dimensions of the snare drum is multiplied by a scale factor of $\frac{1}{2}$

Radius of the snare drum = $\frac{r}{2}$

Ratio of the radius of the snare drum and cylindrical model ,

$\frac{\frac{r}{2}}{R} =\frac{1}{4}$

$\frac{r}{2R}=\frac{1}{4}$

$\frac{r}{R}=\frac{1}{2}$

Therefore, the cylinder with Sara's dimensions will be geometrically similar but the scale factor will be 1 : 2

Option B is the answer.

6 0

2 years ago

Construct the confidence interval for the population mean mu. c = 0.90, x = 16.9, s = 9.0, and n = 45. A 90% confidence inte

Georgia [21]

Answer:

The 90% confidence interval for population mean is $14.7 < \mu < 19.1$

Step-by-step explanation:

From the question we are told that

The sample mean is $\= x = 16.9$

The confidence level is $C = 0.90$

The sample size is $n = 45$

The standard deviation

Now given that the confidence level is 0.90 the level of significance is mathematically evaluated as

$\alpha = 1-0.90$

$\alpha = 0.10$

Next we obtain the critical value of $\frac{\alpha }{2}$ from the standardized normal distribution table. The values is $Z_{\frac{\alpha }{2} } = 1.645$

The reason we are obtaining critical values for $\frac{\alpha }{2}$ instead of that of $\alpha$ is because $\alpha$ represents the area under the normal curve where the confidence level 1 - $\alpha$ (90%) did not cover which include both the left and right tail while $\frac{\alpha }{2}$ is just considering the area of one tail which is what we required calculate the margin of error

Generally the margin of error is mathematically evaluated as

$MOE = Z_{\frac{\alpha }{2} } * \frac{\sigma }{\sqrt{n} }$

substituting values

$MOE = 1.645* \frac{ 9 }{\sqrt{45} }$

$MOE = 2.207$

The 90% confidence level interval is mathematically represented as

$\= x - MOE < \mu < \= x + MOE$

substituting values

$16.9 - 2.207 < \mu < 16.9 + 2.207$

$14.7 < \mu < 19.1$

3 0

3 years ago

Some one plz help me 25 points

qaws [65]

C, a²+b²=c²

why does this have to be 20 characters long

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3 years ago

Is this right??? Please answer

lesya692 [45]

Answer:Yes its correct!(good job)

Step-by-step explanation:If you want to doubule check just count the tens carefully and if your still sketchy about it just cir cle the ones you counted hope this helped!

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3 years ago

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Nata [24]

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