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2 years ago

Math , pleaaaase

Mathematics

1 answer:

Whitepunk [10]2 years ago

4 0

Answer:

The standard deviation is above 6 mm, which means that this batch does not pass the technical control.

Step-by-step explanation:

Mean of the batch:

The mean of the batch is the sum of all values divided by the number of items. So

$M = \frac{31+32+38+34+45+41+24}{7} = 35$

Mean in the desired interval.

Standard deviation:

Square root of the sum of the difference squared between each term and the mean, divided by the number of itens. So

$S = \sqrt{\frac{(31-35)^2+(32-35)^2+(38-35)^2+(34-35)^2+(45-35)^2+(41-35)^2+(24-35)^2}{7}} = 6.46$

The standard deviation is above 6 mm, which means that this batch does not pass the technical control.

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In a certain community, 30% of the families own a dog, and 20% of the families that own a dog also own a cat. It is also known t

Nesterboy [21]

Answer:

a) 0.06

b) 0.778

Step-by-step explanation:

Let's suppose a community of 100 families just to facilitate the calculation.

30% of the families own a dog

Dog = 30% of 100 = 30

20% of the families that own a dog also own a cat = 20% of 30 = 6

27% of all the families own a cat = 27% of 100 = 27

So, 6 families own a dog and a cat.

As 30 families own a dog, [30 - 6 =] 24 families own only dogs

As 27 families own a cat, [27 - 6 = ] 21 families own only cats

See picture attached.

a) What is the probability that a randomly selected family owns both a dog and a cat?

P(dog and cat) = dog ∩ cat/total = 6/100 = 0.06

b) What is the conditional probability that a randomly selected family doesn't own a dog given that it owns a cat?

So, only cat/total cat

P (not dog|cat) = 21/27 = 0.778

3 0

3 years ago

An Indian tepee is a conical tent. Find the number of cubic feet of air in a teepee 10 ft. in diameter and 12 ft. high.

vampirchik [111]

Surface Area of a cone is

pi * r * s + pi * r^2 

s is the side length, since you have 10 ft diameter, you know radius is 5. And since height is 12. With this, you have a 5-12-13 triangle, and s=13. 

so 

pi * 5 * 14 + pi * 5^2 = 95 pi or 298.3 

divide 298.3 by 15 and you get 19.88, you round up, so 20 is the answer

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3 years ago

Mr. Hall deposited money into an account in which interest is compounded quarterly at a rate of 2.6%. How much did he deposit if

Amanda [17]

The formula of this equation would be $x_{0}$ * 1.026^16 = 7,160.06
So from this equation we know that $x_{0} = \frac{7,160.06}{1.026^{16} }$
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3 years ago

What is the sum of the interior angles of a 15-gon?

klemol [59]

Answer:

2340 degrees

Step-by-step explanation:

Each triangle has an angle sum of 180 degrees, therefore the sum of interior angles of 15-gon will be 13×180=2340

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3 years ago

Which equation has no solution?

prohojiy [21]

Answer:

Step-by-step explanation:

C.

5/8x + 25 = 3/8x + 15 + 1/4x
5/8x + 10 = 3/8x + 2/8x
5/8x + 10 = 5/8x
10 = 0

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2 years ago