An atom of a certain element has 21 protons, 21
electrons, and a mass number of 45. How many
neutrons are in this atom?

Answers

Answer 1
45-21=24 neutrons :)

As the generally accepted mass of an electron is 0. So, to find the mass of neutrons, minus the protons from the total mass.

Related Questions

In Ellen's math class, there are 2 boys for every 3 girls. If there are 21 girls in the class, how many boys are in the class?​

Answers

Answer: 14 boys

Step-by-step explanation:

ratio 2:3

7 divided by 21 = 3, so 7 times 2 equals 14

Answer:

14

Step-by-step explanation:

Divide 21 by 3, you get 7. Multiply 7 by 2, you get 14.

If Tn =n^+2n. Find third term of the sequence

Answers

Answer:

The third term of the sequence Tₙ = n² + 2n is:

T₃ = 15

Step-by-step explanation:

Given

As the sequence is given by

Tₙ = n² + 2n

To determine

The third term of the sequence

The third term of the sequence can be determined by substituting n = 3 in the sequence

Tₙ = n² + 2n

T₃ = (3)² + 2(3)

T₃ = 9 + 6

T₃ = 15

Therefore, the third term of the sequence Tₙ = n² + 2n is:

T₃ = 15

p is directly proportional to the cube of q

Answers

Answer:

p=q^3

Step-by-step explanation:

The formula for p  in terms of q is p = 0.4 q³

What is meaning of Direct Proportion ?

Direct Proportion means when one variable changes the other also changes in the same direction by some proportion.

It is given that

p ∝ q³

p = k q³

here k is the proportionality constant

It is also given that when q = 15 , p = 1350

1350 = k * 15³

k = 0.4

Therefore

The formula for p  in terms of q is

p = 0.4 q³

The complete question is

p is directly proportional to the cube of q . When , q = 15 , p = 1350

Find a formula for p  in terms of q

To know more about Direct Proportion

https://brainly.com/question/14664532

#SPJ2

Julie bought 12
packages of cucumber seeds. Each bag contains 42
seeds. If she plants half of the seeds, how many of the
seeds does she have left?

Answers

Answer:

12x42=504

504/2=252

252

Step-by-step explanation:

A rectangular playground has width of 320 feet and a length of 1280 feet. Brooklyn makes a
scale model of the playground using a scale of 4 cm: 20 feet. What are the dimensions of
Brooklyn's scale model?



please help

Answers

Answer:409600

Step-by-step explanation:I multpiled and got 409600

If a confidence interval is given from 43.83 up to 61.97 and the mean is known to be 52.90, what is the margin of error?

Answers

Answer:

error is 9.07

Step-by-step explanation:

lemme know if its wrong

If i want to build a fence around my rectangular yard, what is the area in fencing if one side is 50 feet long and the other is 80 feet wide?

Answers

Answer:

70 feet total

Step-by-step explanation:

Answer:

4,000

Step-by-step explanation:

50•80=4,000

Mrs. Shaw writes this equation on the board. She asks the students to find
the solution.
-40 -2(3m + 1/2)= 7m -2

Keith’s work is shown below. What mistake did Keith make?

-40 - 6m + 1 = 7m - 2
-39 - 6m = 7m -2
-39 = 13m - 2
-37 = 13m
-2 11/13 = m

What is the solution of the equation?

Answers

Answer:

-37=13m

Step-by-step explanation:

3/4 divided by 1/5 PLEASE ANSWER

Answers

Answer:

3.75

Step-by-step explanation:

To make it a fraction form answer, you multiply the dividend numerator by the divisor denominator to make a new numerator.

Furthermore, you multiply the dividend denominator by the divisor numerator to make a new denominator:

To make the answer to 3/4 divided by 1/5 in decimal form, you simply divide the numerator by the denominator from the fraction answer above:

15/4 = 3.75

The answer is rounded to the nearest four decimal points if necessary.

15/4 is an improper fraction and should be written as 3 3/4.

 

 

Answer:

3.75

Step-by-step explanation:

Two angles of a triangle have measures of 55° and 65°.
Which could not be a measure of an exterior angle of the
triangle?

A. 120
B.125
C.130
D.115

Answers

The third angle is 180-55-65 = 60°.

Exterior angles are 180-55 = 125°, 135°, 120°

The sum of an interior angle and an exterior angle is 180°. Then the 130° is not an exterior angle of the triangle.

What is the triangle?

Triangle is a polygon that has three sides and three angles. The sum of the angle of the triangle is 180 degrees.

The two angles of a triangle have measures of 55° and 65°. Then the third angle (x) will be

w + 55° + 65° = 180°

                  w = 180° - 120°

                  w = 60°

Let the exterior angle be x, y, and z.

The sum of an interior angle and an exterior angle is 180°. Then we have

[tex]\rm x = 180^o - 55^o = 125^o \\\\y = 180^o - 65^o = 115^o \\\\z = 180^o - 60^o = 120^o[/tex]

More about the triangle link is given below.

https://brainly.com/question/25813512

3x+4y=11 x-2y=2 solve the system of equations

Answers

Answer
4.667

Step by step explanation

1.1 Solve 14x-3y+2=0

When x=1, then y= ___

Please I need the answer soon.

Answers

Answer:

When x = 1, y = -2

Step-by-step explanation:

The equation of this line is y = x - 3, so when x = 1, y would equal 1 - 3 or -2.

Answer:

x=1, then y= -2

What is the equivalent distance of 60,000 centimeters in kilometers?

1 m = 100 cm

1 km = 1000 m

Enter your answer in the box.

60,000 cm =
km

Answers

Answer: it would be 0.6

Step-by-step explanation: why?, because, you must divided 60,000 by 100,000. To get the kilometer 0.6 I hope this helps :), I also took the test!.

Answer:

0.6

Step-by-step explanation:

the answer above is correct

What is 7300 rounded to the nearest hundred?

Answers

7300 is your answer hope it helps

Can someone solve this please

Answers

Answer:

4. 2.4

5. [tex]0.123 = \frac{123}{1000}[/tex]

6. IV

Step-by-step explanation:

4. 3 < 5, so we don't add a tenth when rounding. Hence the answer is 2.4

5. [tex]0.123 = \frac{123}{1000}[/tex]. Because [tex]123[/tex] isn't divisible by 2 or 5, we know that this is the most simplified form.

6. Putting the I before the V negates the I. So IV = 5 - 1 = 4.

Look at pic plz help

Answers

Answer:

Mochi is growing quicker.

Step-by-step explanation:

At 3 weeks Mochi was 13 pounds but Kappa was only at 11. Hope this helps! I'd really appreciate brainliest.

Answer:

Mochi

Step-by-step explanation:

by 2 weeks Mochi was at weight 9 while Kappa was at 8 in weight the same time.

The age at which small breed dogs are fully housebroken follows a Normal distribution with mean ms = 6 months and standard deviation ss = 2.5 months. The age at which large breed dogs are fully housebroken follows a Normal distribution with mean mL = 4 months and standard deviation sL = 1.5 months. Let xS – xL represent the sampling distribution. Be sure show all work and conditions. Let the sample size for both sets be 25 dogs. Should we be surprised if the sample mean housebroken age for the small breed dogs is at least 2.5 months more than the sample mean housebroken age for the large breed dogs? Explain your answer.

Answers

Answer:

This measure is just 0.17 standard deviations from the mean, so we should not be surprised.

Step-by-step explanation:

Normal probability distribution

When the distribution is normal, we use the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

If the z-score is lower than -2, or higher than 2.5, the score of X is considered unusual.

Subtraction of normal variables:

When we subtract normal variables, the mean is the subtraction of the means, while the standard deviation is the square root of the sum of the variances.

Let xS – xL represent the sampling distribution.

Mean s 6, means L 4. So

[tex]\mu = 6 - 4 = 2[/tex]

Standard deviation s is 2.5, for L is 1.5. So

[tex]\sigma = \sqrt{2.5^2+1.5^2} = 2.915[/tex]

Should we be surprised if the sample mean housebroken age for the small breed dogs is at least 2.5 months more than the sample mean housebroken age for the large breed dogs? Explain your answer.

We have to find the z-score for X = 2.5. So

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{2.5 - 2}{2.915}[/tex]

[tex]Z = 0.17[/tex]

This measure is just 0.17 standard deviations from the mean, so we should not be surprised.

select all the sides lengths that will form a triangle?
A. 14 IN, 5 IN, 9 IN
B. 11 CM, 13, CM, 12 CM
C. 25 MM, 12 MM, 12 MM
D. 10 FT, 24FT, 26 FT
E. 5 YD, 5, YD, 5, YD
F. 18 CM, 46, CM, 26 CM
Thank you! :)

Answers

B

Step-by-step explanation:

11CM, 13CM, 12CM forms a triangle

What is the value of X on the parallelogram below?

Answers

2(x+8) hope its right :))
44 is the correct answer for x
Because (2(44)+16)=104 is a true statement

Corn chips cost 29.5 cents per ounce. If a bag cost $3.87, how many ounces are in the bag of chips?

Answers

Answer:

13.1

Step-by-step explanation:

Answer:

Around 13 ounces

Step-by-step explanation:

Select the statement that describes a unit rate. Javon read 1 book. Javon is running 3 miles. Javon has 4 balls and 1 bat. Javon is bicycling 7 miles per hour.

Answers

Answer:

The last one

Step-by-step explanation:


5. A television set is sale at P13,499 in cash or on installment terms, P2,500 each
month for the next 6 months at 9% compounded monthly. If you would be the
buyer what would you prefer cash or installment?​

Answers

Cash is always king. It will cost you more if you pay interest, but you may not have enough money to buy this very over priced $13,499 TV. I say shop around for a cheaper TV.

If I were the buyer, I would prefer cash payments to paying in instalment.

In order to determine which payment method I would prefer, I would have to determine the future value of the payment in instalment terms.

The formula for calculating future value = A (B / r)

B = [(1 + r)^n] - 1

P2,500 x (1.09^6 - 1) / 0.09 = P18,808.34

Paying in instalments is more expensive.

To learn more about future value, please check: https://brainly.com/question/14640433

In a standardized IQ test scores are normally distributed, with a mean score of 100 and a standard deviation of 15 what is the highest score that would still plays a person in the bottom 10% of the scores

Answers

The 68-95-99.7 Rule Example

Figure 1 illustrates how to apply the 68-95-99.7 Rule to the distribution of IQ scores. In this example, the population mean is 100 and the standard deviation is 15. Based on the 68-95-99.7 Rule, approximately 68% of the individuals in the population have an IQ between 85 and 115.

Plz help me! I’m not sure how to do these!

Answers

Answer:

Step-by-step explanation:

Wait where is the picture

Which of the following is the solution of the system of equations shown?
(2,-2)
(2,2)
(-2,2)
(-2,-2)

Answers

Answer:

(-2,-2)

Step-by-step explanation:

The graph doesn't have unit marks, but you can see that the x- and y-coordinates of the intersection are equal, and they are both negative.

(-2,-2)

What is the square root of 7?

Answers

Answer: 2.64575

Explanation:

Answer:

2.64575

Step-by-step explanation:

Micah is twice as old as Richard. Richard is three times as old as Ken. Ken is six years old. How old is Micah?

Answers

Answer:

36

Step-by-step explanation:

Ken = 6 yo

6 *3 = 18

Richard = 18 yo

8 * 2 = 36

Micah = 36

The age of Micah is 36 years.

What is arithmetic operation?

A subfield of mathematics known as arithmetic operations deals with the study and application of numbers to all other subfields of mathematics. Operations like addition, subtraction, multiplication, and division make up the bulk of it.

These fundamental mathematical operations  (+, -, ×, and ÷) that we use every day.

Given age of Ken = 6 years

let age of Micah be m and age of Richard be r

acc. to condition

Micah is twice as old as Richard

m = 2r

Richard is three times as old as Ken

r = 3 ken

r = 3 x 6

r = 18

Richard age is 18 years.

m =2r

m = 2 x 18

m = 36 years

Hence age of Micah is 36 years.

Learn more about arithmetic operation;

https://brainly.com/question/25834626

#SPJ2

David measured a line to be 13.5 inches long. If the actual length of the line is 16.6 inches, then what was the percent error of the measurement, to the nearest tenth of a percent?

Answers

Answer:

18.67

Step-by-step explanation:

(l2-l1)/l2 * 100%

where l2=16.6

l1=13.5

Answer:-23

Step-by-step explanation:

What is the equation of the line that is parallel to the
given line and passes through the point (-2, 2)?

Answers

Answer:

undefined

Step-by-step explanation:

A zoo worker works 189.25 hours in 23 days. If she works the exact same number of hours per day, how many hours does she work each day?

Answers

You have to divide 189.25 hours by 23 days.
Other Questions
Laura puts her file cabinet on a small cart with wheels which will occur. A Laura will increase the amount of friction. B Laura will reduce the force she needs C Laura will decrease the amount of motion D Laura will increases the force she needs A boat has a porthole window, of area 0.00849 m^2, 6.25 m below the surface. The density of sea water is 1027 kg/m^3. The air inside the boat is at 1 atm. What is the net force on the window? long division: Problem type 2 Divide, (12x3 +14x2+24x+9) = (4x2+2x) Your answer should give the quotient and the remainder Quotient: 3 3 Remainder: 1 X ? Some people prefer to have many friends, while others prefer to have only one or two close friends. Think carefully about this idea.Write an essay stating your position on whether it is better to have many friends or a few close friends.Be sure tostate your position clearlyuse appropriate organizationprovide specific support for your argumentchoose your words carefullyedit your writing for grammar, mechanics, and spelling $12 per pizza how many pizzas can i get for $400 If a triangle ABC is classified as a right triangle, which statement is true? What was the outcome of William Backnell's first trip When scientists compare molecular clocks between species, theyhave to use the same segment of DNA. Which of these statementswould explain why that is necessary?A. Not every segment of DNA mutates.B. Different genes mutate at different rates.C. Species accumulate neutral mutations at random rates.D. All mutations cause harmful effects.Check Answer PLEASE HELP ME I WILL GIVE BRAINLIEST A company currently using an inspection process in its material receiving department is trying to install an overall cost reduction program. One possible reduction is the elimination of one inspection position. This position test material has a defective content on the average of 0.04. By inspecting all items, the inspector is able to remove all defects. The inspector can inspect 50 units per hour. The hourly rate including fringe benefits for this position is $9. If the inspection position is eliminated, defects will go into product assembly and will have to be replaced later at a cost of $10 each when they are detected in final product testing.Required:a. If the inspector position is eliminated, what will the hourly cost of defects be?b. Should this inspection position be eliminated?c. What is the cost to inspect each unit?d. Is there benefit (or loss) from the current inspection process? How much? Which number line shows the solution of -3x+6>12? What does -2 - 10 equal to? Which statement best summarizes the success of Reconstruction inSouth Carolina in creating educational opportunities for AfricanAmericans?A. South Carolina schools were fully integrated, allowing AfricanAmericans greater educational opportunity.B. A number of colleges and universities were created in SouthCarolina specifically for African Americans.C. African Americans in South Carolina were granted funds to createa public school system for freedmen.D. The Freedmen's Bureau created many schools, educating AfricanAmericans of all ages in South Carolina. In the figure, BC is a support for the roofof a garage. What is the length of BC? I will give brainliest. Please help fast! (Solve for number 5) Help me in number 10 please 6 points!!!! Which of the following are reasons that Mendel used pea plants in his genetic experiments?Select all that apply.A Peas were the only thing available at the monastery.B Pea plants grow fast.C Pea plants are easy to grow.D Pea plants have several distinct traits that vary. Two airplanes leave an airport at the same time on different runways. One flies on a bearing of N 66W at 325 miles per hour. The other airplane flies on a bearing of S 26W at 300 miles per hour. How far apart will the airplanes be after two hours Graph y + 2 = -1(x + 3). Answer the eqation 6h=-24