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never [62]
1 year ago
7

Evaluate the expression 21 ÷ 3 + 8 − 4. A) 19 B) 17 C) 15 D) 11

Mathematics
2 answers:
N76 [4]1 year ago
6 0

Answer:

D) 11

Step-by-step explanation:

Division and multiplication always comes first in an equation. Since there is no multiplication in the expression, we can divde first.

21 / 3 = 7

Our new expression will be: 7 + 8 - 4

Now we can just add (7) , (8), and (-4) not caring about the order, since they are all addition or subtraction.

I'll do the addition first, but order does not matter.

7 + 8 = 15

15 - 4 = 11

So 11 is our final answer.

Looking at the answer choices, D has 11, so D is our answer for this question.

nirvana33 [79]1 year ago
5 0

Answer:

D

Step-by-step explanation:

We will use the order of operations to evaluate the expression.

From left to right , Multiplication/Division followed by Addition/Subtraction.

21 / 3 + 8 - 4

= 7 + 8 - 4

= 15 - 4

= 11

Therefore, the answer is D

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According to the Census Bureau, in 2014 California had an estimated population of 3.88 x 10^7 and Wyoming had an population of 5
Verdich [7]
The population of California is 3.88 x 10^7 - 5.84 x 10^5 = 3.82 x 10^7 more than the population of Wyoming. Alternatively the population of California is 3.88 x 10^7 / 5.84 x 10^5 = 66 times the population of Wyoming. 

Thank you for posting your question here at brainly. I hope the answer will help you. Feel free to ask more questions.
8 0
3 years ago
An electronics company produces​ transistors, resistors, and computer chips. Each transistor requires 3 units of​ copper, 1 unit
padilas [110]

Answer:

An electronics company can be produce 350 transistors and 340 computer chips, they can´t produce resistors.

Step-by-step explanation:

1. We will name the variables for transistors, resistors and the computer chips.

a = Transistors

b= Resistors

c = Computer chips

2. We propose three linear equations, one for the copper, one for the zinc and one for the glass.

\left \{ {{3a+3b+2c=1730} \atop {a+2b+c=690}}\atop {2a+b+2c=1380}} \right.

3. We write the matrix form as Ax=d

A=\left(\begin{array}{ccc}3&3&2\\1&2&1\\2&1&2\end{array}\right)

x=\left(\begin{array}{ccc}a\\b\\c\end{array}\right)

A=\left(\begin{array}{ccc}1730\\690\\1380\end{array}\right)

With this formula the solution of x is x=\frac{d}{A} or x=A^{-1}d

4. We will find the inverse matrix A^{-1} using the formula:

A^{-1} = \frac{1}{detA} (C_{A})^{T}

a. det A

det A=\left[\begin{array}{ccc}3&3&2\\1&2&1\\2&1&2\end{array}\right] =3*(4-1)-3*(2-2)+2*(1-4)=9-0-6=3

b. (C_{A})^{T}

C_{A}=\left(\begin{array}{ccc}4-1&.(2-2)&1-4\\-(6-2)&6-4&-(3-6)\\3-4&-(3-2)&6-3\end{array}\right)

C_{A}=\left(\begin{array}{ccc}3&.0&-3\\-4&2&3\\-1&-1&3\end{array}\right)

(C_{A}) ^T=\left(\begin{array}{ccc}3&0&-3\\-4&2&3\\-1&-1&3\end{array}\right)^T

(C_{A}) ^T=\left(\begin{array}{ccc}3&-4&-1\\0&2&-1\\-3&3&3\end{array}\right)

c.A^{-1}

A^{-1}=\frac{1}{3} \left(\begin{array}{ccc}3&-4&-1\\0&2&-1\\-3&3&3\end{array}\right)

5. As x=\frac{d}{A} or x=A^{-1}d, the solution of x is:

x=\frac{1}{3}\left(\begin{array}{ccc}3&-4&-1\\0&2&-1\\-3&3&3\end{array}\right)\left(\begin{array}{ccc}1730\\690\\1380\end{array}\right)

x=\frac{1}{3}\left(\begin{array}{ccc}(3*1730)+(-4*690)+(-1*1380)\\(0*1730)+(2*690)+(-1*1380)\\(-3*1730)+(3*690)+(3*1380)\end{array}\right)

x=\frac{1}{3}\left(\begin{array}{ccc}1050\\0\\1020)\end{array}\right)

X=\left[\begin{array}{ccc}350\\0\\340\end{array}\right]

<u><em>Therefore:</em></u>

<u><em>a= 350 Transistors</em></u>

<u><em>b=0 Resistors</em></u>

<u><em>c=340 Computer chips</em></u>

4 0
2 years ago
The volume of a cube is 36 cubic feet. What is the volume of a pyramid that fits exactly inside the cube?
jok3333 [9.3K]
Volume of a cube = 1/3 volume of cube = 1/3 * 36 = 12 cubic feet.

6 0
3 years ago
I need #1 done (show work) will give brainliest
allochka39001 [22]

Step-by-step explanation:

<u>Statement                                                        Reason                               </u>

∠5 and ∠7 are vertical angles                        Vertical angles theorem

m∠5 = m∠7                                                      Definition of vertical angles

m∠5 = -2(3x - 4), m∠7 = 3(x - 3) - 1                  Given

-2(3x - 4) = 3(x - 3) - 1                                       Substitution property of equality

-6x + 8 = 3x - 9 - 1                                            Distributive property

3x + 6x = 8 + 10                                               Addition property

9x = 18                                                              Addition property

x = 18/9                                                             Division property

x = 2                                                                  Proved

6 0
2 years ago
A survey found that​ women's heights are normally distributed with mean 63.3 in. and standard deviation 2.7 in. The survey also
mylen [45]

Answer:

A) There is a 100% chance of meeting the height requirement for women.

B) There is a 99.89% chance of meeting the height requirement for men.

C) New height requirements are:

71.9 inches for men and 58.9 inches minimum for women.

At least 58.9 inches and at most 71.9 inches.

Step-by-step explanation:

This question involves finding z values which tell us the percentage from 0 to x.

z = (x-μ)/σ

A) In this question, the minimum sample point is 4 ft 9 inches or converting to inches, we have;(4*12) + 9 =57 inches.

The maximum sample point is 6 ft 4 inches which in inches gives; (6*12) + 4 = 76 inches

For the minimum point;

z = (57 - 63.3)/2.7 = -2.33

From the z-distribution table, this equates to 0.0099.

The maximum;

z = (76 - 63.3)/2.7 = 4.70

From the z-table, it gives 0.999.. Basically 100%.

So there is a 100% chance of meeting the height requirement for women.

B) For men;

the minimum z = (57 - 67.3)/2.8 = -3.68 which gives 0.00012 from the z-distribution table.

The maximum;

z = (76 - 67.3)/2.8 = 3.07 which gives 0.9989 from the z-distribution table. Basically, 99.89%.

So there is a 99.89% chance of meeting the height requirement for men.

C) To exclude the tallest 5% of men, we need to find the z-value for 0.95 and then solve for x.

Thus from the z-table, z = 1.65. So;

1.645 = (x - 67.3)/2.8

4.606 = x - 67.3

x = 67.3 + 4.606

x ≈ 71.9 inches for men.

So, Current minimum is okay.

To exclude the shortest 5% of women, we need to find the z for 0.05.

From the z-distribution table, it has a value of -1.645. So;

-1.645 = (x - 63.3)/2.7

-4.4415 = x - 63.3

x = 63.3 - 4.4415

x ≈ 58.9 inches minimum.

So, Current maximum is okay.

5 0
3 years ago
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