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3 years ago

5

The radius of a cylinder is 3x - 2 cm. The height of the cylinder is x + 3 cm. What is the surface area of the cylinder? Use the

formula A = 2πr^2 + 2πrh.
A. 2π(3x^2 + 10x - 8)
B. 2π(12x^2 + 7x - 2)
C. 2π(12x^2 - 2x +13)
D. 2π(12x^2 - 5x -2)

1 answer:

Anestetic [448]3 years ago

7 0

Surface area = 2 pi (3x-2)^2 + 2 pi (3x -2) ( x + 3)

= 2 pi (9x^2 - 12x + 4 + 3x^2 + 7x - 6

= 2pi(12x^2 - 5x - 2)

Its D

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Steve's scores on 6 of his tests were 92, 78, 86, 92, 95, and 91. If he took a seventh test and raised the mean of his scores by

monitta

Answer:

96

Step-by-step explanation:

First we need to know the mean of the Steve's scores on 6 of his tests. Given the six scores as 92, 78, 86, 92, 95, and 91.

Mean = sum of the scores/Total test taken

Mean = 92+78+86+92+95+ 91/6

Mean = 534/6

Mean = 89

If he took the seventh test and the mean score is raised by 1 them the new mean will be expressed as;

New mean = 92+78+86+92+95+ 91+x/7 = 89+1

Where x is the new score. Note that of a new score is added, the total year taken will also change to 7

To get x;

92+78+86+92+95+ 91+x/7 = 89+1

92+78+86+92+95+ 91+x/7 = 90

534+x/7 = 90

Cross multiply

533+x = 90×7

533+x = 630

x = 630-534

x = 96

Hence the score of the seventh test is 96

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Read 2 more answers

Find the z score that cuts-off the largest 9% under the standard normal curve. a) -1.34 b) 1.34 c) 0.536 d) 1.28

topjm [15]

Answer:

b) 1.34

Step-by-step explanation:

The z score is used to determine the number of standard deviations by which the raw score is above or below the mean. If the z score is positive then the z score is above the mean while for a negative z score implies that it is below the mean. The z score is given by:

$z=\frac{x-\mu}{\sigma}$

For the largest 9%, the score is 100% - 9% = 91% = 0.91

From the normal distribution table, the z score that corresponds to 0.91 is 1.34

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3 years ago