Put these number in order of size, smallest to largest:

The floor of a skating rink is circular and has a radius of 14 meters. What is the

Lerok [7]

Answer:

Step-by-step explanation:

615.75m squared

4 0

2 years ago

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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

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Jackson’s age was 2/fifth of the age he will be 20 years from now seven years ago. How old is Jackson now?

Margaret [11]

Let's say Jackson's age now is x.

In 20 years, (so 20+x), Jackson seven years ago will be 2/5ths of that age.

So 2/5(20+x)=x-7

Then you solve the equation
8+2/5x=x-7
15=3/5x
x=25
Jackson is 25 years old.

Let's check our answer! In 20 years, Jackson will be 45. 7 years ago, he was 18. 2/5 of 45 is 18. Our answer is correct!

5 0

3 years ago

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Find the value of x so that the line passing through the points will have the given slope: (x,6) and (10,-3) with a slope of -3/

Lana71 [14]

$(x,6) \\
x_1=x \\
y_1=6 \\ \\
(10,-3) \\
x_2=10 \\ y_2=-3 \\ \\
\hbox{the slope: } m=\frac{y_2-y_1}{x_2-x_1}=\frac{-3-6}{10-x}=\frac{-9}{10-x} \\ \\
m=-\frac{3}{2} \\
\Downarrow \\
-\frac{3}{2}=\frac{-9}{10-x} \\
-\frac{3}{2}(10-x)=-9 \\
10-x=-9 \times (-\frac{2}{3}) \\
10-x=3 \times 2 \\
10-x=6 \\
-x=6-10 \\
-x=-4 \\
\boxed{x=4}$

6 0

3 years ago

The length of a rectangle is 10 meters more than the width. If 3 meters is added to both the length and the width, the new area

Finger [1]

Answer:

L = 20

W = 10

Step-by-step explanation:

L = (w + 10)

NL = (w + 13)

Divide 299 by 13:

299 ÷ 13 = 23

So, 23 x 13 = 299

L = 23

W = 13

Subtract 3 from both to get the original length and width

4 0

3 years ago