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3 years ago

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The classroom encyclopedia set seems to fill a shelf that is 24 in long each book is 3/4 in thick how many books are in the clas

sroom set

1 answer:

gavmur [86]3 years ago

7 0

24 divided by 3/4= 24*4/3=32books

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Hi! Please help I am very desperate and I need it solved. Thanks!

RideAnS [48]

Answer:

I think the answer is 80?

Step-by-step explanation:

8 0

3 years ago

A true-false quiz with 10 questions was given to a statistics class. Following is the probability distribution for the score of

disa [49]

Answer:

$E(X)=\sum_{i=1}^n X_i P(X_i)$

And if we use the values obtained we got:

$E(X)=5*0.05 +6*0.15 +7*0.33 +8*0.28+ 9*0.12 +10*0.07=7.48$

For this case this value means that the expected score is about 7.48

Step-by-step explanation:

For this case we assume the following probability distribution:

X 5 6 7 8 9 10

P(X) 0.05 0.15 0.33 0.28 0.12 0.07

First we need to find the expected value (first moment) and the second moment in order to find the variance and then the standard deviation.

In order to calculate the expected value we can use the following formula:

$E(X)=\sum_{i=1}^n X_i P(X_i)$

And if we use the values obtained we got:

$E(X)=5*0.05 +6*0.15 +7*0.33 +8*0.28+ 9*0.12 +10*0.07=7.48$

For this case this value means that the expected score is about 7.48

In order to find the standard deviation we need to find first the second moment, given by :

$E(X^2)=\sum_{i=1}^n X^2_i P(X_i)$

And using the formula we got:

$E(X^2)=(5^2 *0.05)+(6^2 *0.15)+(7^2 *0.33)+(8^2 *0.28)+ (9^2 *0.12 +(10^2 *0.07))=57.46$

Then we can find the variance with the following formula:

$Var(X)=E(X^2)-[E(X)]^2 =57.46-(7.48)^2 =1.5096$

And then the standard deviation would be given by:

$Sd(X)=\sqrt{Var(X)}=\sqrt{1.5096}=1.229$

5 0

3 years ago

Read 2 more answers

The length of a rectangular garden is represented by 3x-4 and the width is represented by 2x-5. Which of the following represent

lisabon 2012 [21]

Well area of a rectangle is given by the equation

a = L x W

Since they give us the expression for length and width we can find the expression for the area...

a = (3x - 4) x (2x - 5) or simply
a = (3x -4)(2x - 5)

Now we multiply

6x^2 - 15x - 8x + 20 =
6x^2 - 23x + 20

Your answer is C.

8 0

3 years ago

Amy invites 800 people to her pool

antiseptic1488 [7]

Answer:

400

Step-by-step explanation:

4 0

2 years ago

I really need help do can someone do it step by step so I can understand plzzzz

Alekssandra [29.7K]

Answer:

64 × pi m²

Step-by-step explanation:

the formulas needed for the surface area of a cone are :

base area plus the "mantle", the lateral "wall" around it.

the base area is a circle.

so, that formula is Ac = pi×r²

the "wall" formula is Aw = pi×r×s

r = radius

s = slant height = 12

the formula for the surface area of a sphere is

As = 4×pi×r²

we know now, that both surface areas are the same, and also the radius is the same for both objects.

Ac + Aw = As

pi×r² + 12×pi×r = 4×pi×r²

=>

12×pi×r = 3×pi×r²

12×pi = 3×pi×r

12 = 3×r

r = 4 m

now, we only need to use this value of r in our formulas for surface areas, like for the sphere :

4×pi×r² = 4×pi×4² = 4³×pi = 64×pi

3 0

2 years ago