1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Firlakuza [10]
3 years ago
5

What is the value of y in the equation y − 7 = 21? (4 points)

Mathematics
2 answers:
labwork [276]3 years ago
8 0

Answer:

4

Step-by-step explanation:

y-7=21

+7 +7

y=21+7

y=28

Ugo [173]3 years ago
6 0

Answer:

4) 28

Step-by-step explanation:

Isolate the y

add 7 to both sides

y - 7  = 21

y - 7 (+7) = 21 (+7)

y = 21 + 7

y = 28

28 is your answer

hope this helps :D

You might be interested in
63 plus what gives you 83
iVinArrow [24]
83-63=20
So your answer is 20
5 0
3 years ago
A statistician calculates that 8% of Americans own a Rolls Royce. If the statistician is right, what is the probability that the
hichkok12 [17]

Answer:

0.007 = 0.7% probability that the proportion of Rolls Royce owners in a sample of 595 Americans would differ from the population proportion by more than 3%

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the z-score of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

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 p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean \mu and standard deviation \sigma, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean \mu and standard deviation s = \frac{\sigma}{\sqrt{n}}.

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean \mu = p and standard deviation s = \sqrt{\frac{p(1-p)}{n}}

A statistician calculates that 8% of Americans own a Rolls Royce.

This means that p = 0.08

Sample of 595:

This means that n = 595

Mean and standard deviation:

\mu = p = 0.08

s = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\frac{0.08*0.92}{595}} = 0.0111

What is the probability that the proportion of Rolls Royce owners in a sample of 595 Americans would differ from the population proportion by more than 3%?

Proportion above 8% + 3% = 11% or below 8% - 3% = 5%. Since the normal distribution is symmetric, these probabilities are equal, and so we find one of them and multiply by 2.

Probability the proportion is less than 5%:

P-value of Z when X = 0.05. So

Z = \frac{X - \mu}{\sigma}

By the Central Limit Theorem

Z = \frac{X - \mu}{s}

Z = \frac{0.05 - 0.08}{0.0111}

Z = -2.7

Z = -2.7 has a p-value of 0.0035

2*0.0035 = 0.0070

0.007 = 0.7% probability that the proportion of Rolls Royce owners in a sample of 595 Americans would differ from the population proportion by more than 3%

8 0
3 years ago
Identify the percent of change as an increase or a decrease. 50 pounds to 35 pounds. Find the percent of change.
Solnce55 [7]
Since it starts at 50 and goes to 35....it is a decrease since the amount is going down, or getting smaller.  To find the percent, first find the difference 50-35 = 15; then divide by the initial amount of 50.  So, 15/50 = 0.3, and then convert that to a percent by multiplying by 100.  Therefore the percent decrease is 30%
5 0
3 years ago
Read 2 more answers
Josh is building a sandbox for his little sister. He uses these plans, which have a scale of 2 in. : 3 ft.
skelet666 [1.2K]

Answer:

Width of 6ft and length of 9ft

Step-by-step explanation:

The sandbox has a ratio of 2:3. If you plug the numbers in with the ratio, you can find the actual dimensions.

Let x be the length

Let y be the width

(Length)

2in / 3ft = 6in / (x)ft

2in / 3ft = 6in / <u><em>9ft </em></u>

(Width)

2in / 3ft = 4in / (y)ft

2in / 3ft = 4in / <em><u>6ft</u></em>

6 0
2 years ago
Question 3<br> Solve this system by using the elimination method.<br> 4x + 2y = 8<br> 5x + 3y = 9
umka21 [38]

Answer:

x=3, y=-2. (3, -2).

Step-by-step explanation:

4x+2y=8

5x+3y=9

---------------

simplify 4x+2y=8 into 2x+y=4

-----------------

2x+y=4

5x+3y=9

----------------

y=4-2x

5x+3(4-2x)=9

5x+12-6x=9

-x=9-12

-x=-3

x=3

2(3)+y=4

6+y=4

y=4-6

y=-2

7 0
3 years ago
Other questions:
  • a school principal orders 75 boxes of chalk. Each box has 12 stick of chalk. The school has 23 teachers. Does the principal have
    13·1 answer
  • Solve 8x-5&gt;or=27<br> Epic<br> Epic<br> Epic<br> Epic<br> Epic<br> Gamer momeent
    6·2 answers
  • How many significant figures does 120 have
    11·1 answer
  • There were n signers of the Declaration of Independence. The oldest was Benjamin Franklin, who was y years old. 7 is 10% of y. W
    12·1 answer
  • Mathematical statements into logical statements with nested quantifiers. About Translate each of the following English statement
    8·1 answer
  • Textbook search committee is considering 13 bucks for possible adoption committee has decided to select six of the 13 for furthe
    8·1 answer
  • How is the equation of this circle written in standard form?<br><br> x2 + y2 - 6x + 14y = 142
    7·1 answer
  • PLEASE HELP ME! IT A TEST AND THE TEACHER WAITING ON ME!! I NEED ANSWERS QUICK I HAVE 5 PICTURES SO LOOK PLEASE TECHNOLOGY HISTO
    12·1 answer
  • What is the area of the figure below?
    13·1 answer
  • Help me find the area here! 6th grade math
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!