Use cubes. color and draw to show a way to take apart 7.

The mean of five numbers 3,7,9,12, and x is 8. Find the value of x

jeyben [28]

Answer: " x = 9 " .
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Explanation:
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To calculate the mean:
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The mean =

     {the sum of all the values in the number set} ÷

     {the number of values in the data set} ;
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To solve for "x" ;
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Given that the "mean" is: "8" ;
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           8  = { 3 + 7 + 9 + 12 + x } / 5 ;
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    ↔ { 3 + 7 + 9 + 12 + x } / 5   = 8 ;
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            → { 3 + 7 + 9 + 12 + x } = 8 * 5 ;
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            → { 31 + x } = 40 ;
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            ↔   x + 31 = 40 ;
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       Subtract "31" from EACH SIDE of the equation; to isolate "x" on one side of the equation; and to solve for "x" ;
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            →   x + 31 − 31 = 40 − 31 ;

                       →  x = 9 .
____________________________________

7 0

3 years ago

Which of the following figures has a length, width, and height?

rodikova [14]

Answer:

I believe

D. Pyramid

Is the answer I did it in 6th or 7th grade

Step-by-step explanation:

Square is flat so no height.

Line segment is a flat line so no height

point is a literal dot

pyramid is a 3d figure so it would have all of the attributes

We both helped right?

5 0

3 years ago

Read 2 more answers

Suppose you toss a fair coin 10 times, let X denote the number of heads. (a) What is the probability that X=5? (b) What is the p

zubka84 [21]

Answer: The required answers are

(a) 0.25, (b) 0.62, (c) 6.

Step-by-step explanation: Given that we toss a fair coin 10 times and X denote the number of heads.

We are to find

(a) the probability that X=5

(b) the probability that X greater or equal than 5

(c) the minimum value of a such that P(X ≤ a) > 0.8.

We know that the probability of getting r heads out of n tosses in a toss of coin is given by the formula of binomial distribution as follows :

$P(X=r)=^nC_r\left(\dfrac{1}{2}\right)^r\left(\dfrac{1}{2}\right)^{n-r}.$

(a) The probability of getting 5 heads is given by

$P(X=5)\\\\\\=^{10}C_5\left(\dfrac{1}{2}\right)^5\left(\dfrac{1}{2}\right)^{10-5}\\\\\\=\dfrac{10!}{5!(10-5)!}\dfrac{1}{2^{10}}\\\\\\=0.24609\\\\\sim0.25.$

(b) The probability of getting 5 or more than 5 heads is

$P(X\geq 5)\\\\=P(X=5)+P(X=6)+P(X=7)+P(X=8)+P(X=9)+P(X=10)\\\\=^{10}C_5\left(\dfrac{1}{2}\right)^5\left(\dfrac{1}{2}\right)^{10-5}+^{10}C_6\left(\dfrac{1}{2}\right)^6\left(\dfrac{1}{2}\right)^{10-6}+^{10}C_7\left(\dfrac{1}{2}\right)^7\left(\dfrac{1}{2}\right)^{10-7}+^{10}C_8\left(\dfrac{1}{2}\right)^8\left(\dfrac{1}{2}\right)^{10-8}+^{10}C_9\left(\dfrac{1}{2}\right)^9\left(\dfrac{1}{2}\right)^{10-9}+^{10}C_{10}\left(\dfrac{1}{2}\right)^{10}\left(\dfrac{1}{2}\right)^{10-10}\\\\\\=0.24609+0.20507+0.11718+0.04394+0.0097+0.00097\\\\=0.62295\\\\\sim 0.62.$

(c) Proceeding as in parts (a) and (b), we see that

if a = 10, then

$P(X\leq 0)=0.00097,\\\\P(X\leq 1)=0.01067,\\\\P(X\leq 2)=0.05461,\\\\P(X\leq 3)=0.17179,\\\\P(X\leq 4)=0.37686,\\\\P(X\leq 5)=0.62295,\\\\P(X\leq 6)=0.82802.$

Therefore, the minimum value of a is 6.

Hence, all the questions are answered.

3 0

4 years ago

Write the function in standard form<br><br> f(x) = -4 (x - 6)^2 + 15

amid [387]

9514 1404 393

Answer:

f(x) = -4x^2 +48x -129

Step-by-step explanation:

It usually works well to compute the square first. That is, simplify according to the order of operations.

f(x) = -4(x^2 -12x +36) +15

f(x) = -4x^2 +48x -144 +15

f(x) = -4x^2 +48x -129

7 0

2 years ago

Read 2 more answers

The equation for the pH of a substance is pH = –log[H+], where H+ is the concentration of hydrogen ions. Which equation models t

Zanzabum

Answer: [H+] = 10^-7.2

Step-by-step explanation:

Given that the PH of the solution = 7.2

Using the formula pH = –log[H+]. To get the H+ concentration from the pH, raise both sides by the base of 10. Then we have

10^ -pH = H+. with pH of 7.2,

Thus the answer to this problem is

[H+] = 10^-7.2

8 0

3 years ago