What the answer fast

Answer:

equation is pv=nRT

p, n, R are constants

so, v is directly proportional to Temperature

v1/v2=T1/T2

250/v2=300/420

v2=350

Answer:

Stratified sampling

Step-by-step explanation:

Samples may be classified as:

Convenient: Sample drawn from a conveniently available pool.

Random: Basically, put all the options into a hat and drawn some of them.

Systematic: Every kth element is taken. For example, you want to survey something on the street, you interview every 5th person, for example.

Cluster: Divides population into groups, called clusters, and each element in the cluster is surveyed.

Stratified: Also divides the population into groups. However, then only some elements of the group are surveyed.

In this question:

Population divided into groups. Some members of each group are surveyed. This is stratified sampling

Answer:

1341.75

Step-by-step explanation:

I did the math :)

The guy above me is correct

Hey there! I'm happy to help!

We see that if the river isn't moving at all the boat can move at 18 mph (most likely because it has an engine propelling it.)

We want to set up a proportion where our 21 miles downstream time is equal to our 15 miles upstream time so we can find the speed. A proportion is basically showing that two ratios are equal. Since our downstream distance and upstream distance can be done in the same amount of time, we will write it as a proportion.

We want to find the speed of the river. We will use r to represent the speed of the river. When going downstream, the boat will go faster, so it will have a higher mph. So, our speed going down is 18+r. When you are going upstream, it's the opposite, so it will be 18-r.

[tex]\frac{distance}{speed} =\frac{21}{18+r} = \frac{15}{18-r}[/tex]

So, how do we figure out what r is now? Well, one nice thing to know about proportions is that the product of the items diagonal from each other equals the product of the other items. Basically, that means that 15(18+r) is equal to 21(18-r). This is a very nice trick to solve proportions quickly. We see that we have made an equation and now we can solve it!

15(18+r)=21(18-r)

We use the distributive property to undo the parentheses.

270+15r=378-21r

We subtract 270 from both sides.

15r=108-21

We add 21 to both sides.

36r=108

We divide both sides by 36.

r=3

Therefore, the speed of the river is 3 mph.

You also could have noticed that 18mph to 21 mph is +3, and 18mph to 15 mph -3 in -3 mph, so the speed of the river is 3 mph. That would have been a quicker way to solve it XD!

Have a wonderful day!

Answer:

(a)The median for the longboards was 13.5 days, and the median for the shortboards was 13 days, showing that those with longboards typically surfed more days in this month.

(b)The interquartile range for the longboards was 10 days, and the interquartile range for the shortboards was 10.5 days, showing more variation in the days surfed this month for the shortboards.

Step-by-step explanation:

Longboard:

2, 7, 16, 13, 10, 18, 7, 8, 15, 15, 19, 17, 3, 10, 11, 16, 24 5, 20, 6, 9, 11, 8, 21, 22, 18, 14, 12, 16, 24

Sorting in ascending order, we have:

[tex]2, 3, 5, 6, 7, 7, \boxed{8, 8}, 9, 10, 10, 11, 11, 12, \boxed{13, 14,} 15,15, 16, 16, 16, 17, \boxed{18, 18}, 19, 20, 21, 22, 24 , 24[/tex]

Median [tex]=\dfrac{13+14}{2}=13.5[/tex]

[tex]Q_1=\dfrac{8+8}{2}=8 \\Q_3=\dfrac{18+18}{2}=18\\$Interquartile range, Q_3-Q_1=18-8=10[/tex]

Shortboard

17, 16, 7, 5, 13, 8, 7, 6, 15, 8, 8, 16, 10, 23, 24, 10, 20, 16, 16, 24, 23, 14, 6, 12, 10, 7, 12, 25, 13, 22

Sorting in ascending order, we have:

[tex]5, 6, 6, 7, 7, 7, \boxed{8, 8,} 8, 10, 10, 10, 12, 12, \boxed{13, 13} 14, 15, 16, 16, 16, 16, \boxed{17, 20,} 22, 23, 23, 24, 24, 25[/tex]

Median [tex]=\dfrac{13+13}{2}=13[/tex]

[tex]Q_1=\dfrac{8+8}{2}=8 \\Q_3=\dfrac{17+20}{2}=18.5\\$Interquartile range, Q_3-Q_1=18.5-8=10.5[/tex]

Therefore:

(a)The median for the longboards was 13.5 days, and the median for the shortboards was 13 days, showing that those with longboards typically surfed more days in this month.

(b)The interquartile range for the longboards was 10 days, and the interquartile range for the shortboards was 10.5 days, showing more variation in the days surfed this month for the shortboards.

Answer:

we dont see aa figure

Step-by-step explanation:

Answer:

Step-by-step explanation:

Part A

Mean = (2.2 + 2.4 + 2.5 + 2.5 + 2.6 + 2.7)/6 = 2.48

Standard deviation = √(summation(x - mean)²/n

n = 6

Summation(x - mean)² = (2.2 - 2.48)^2 + (2.4 - 2.48)^2 + (2.5 - 2.48)^2 + (2.5 - 2.48)^2 + (2.6 - 2.48)^2 + (2.7 - 2.48)^2 = 0.1484

Standard deviation = √(0.1484/6

s = 0.16

Standard error = s/√n = 0.16/√6 = 0.065

Part B

Confidence interval is written as sample mean ± margin of error

Margin of error = z × s/√n

Since sample size is small and population standard deviation is unknown, z for 98% confidence level would be the t score from the student t distribution table. Degree of freedom = n - 1 = 6 - 1 = 5

Therefore, z = 3.365

Margin of error = 3.365 × 0.16/√6 = 0.22

Confidence interval is 2.48 ± 0.22

Part C

We would set up the hypothesis test. This is a test of a single population mean since we are dealing with mean

For the null hypothesis,

H0: µ = 2.3

For the alternative hypothesis,

H1: µ > 2.3

This is a right tailed test

Since the number of samples is small and no population standard deviation is given, the distribution is a student's t.

Since n = 6

Degrees of freedom, df = n - 1 = 6 - 1 = 5

t = (x - µ)/(s/√n)

Where

x = sample mean = 2.48

µ = population mean = 2.3

s = samples standard deviation = 0.16

t = (2.48 - 2.3)/(0.16/√6) = 2.76

We would determine the p value using the t test calculator. It becomes

p = 0.02

Assuming significance level, alpha = 0.05.

Since alpha, 0.05 > than the p value, 0.02, then we would reject the null hypothesis. Therefore, At a 5% level of significance, the sample data showed significant evidence that the mean absolute refractory period for all mice when subjected to the same treatment increased.

Answer:

873

Step-by-step explanation:

so the equation is: 5x+1

sum is:

[tex] \frac{first \: one \: + \: last \: one}{2} \times quantity \: of \: terms \\ [/tex]

we have 6( 5×1+1) to 91 (5×18+1)

so we have 18 terms

then:

[tex] \frac{91 + 6}{2} \times 18 = 873[/tex]

Answer:

[tex]t=\frac{50.857-51}{\frac{5.014}{\sqrt{7}}}=-0.075[/tex]    

The degrees of freedom are given by:

[tex]df=n-1=7-1=6[/tex]  

The p value for this case would be given:

[tex]p_v = 2*P(t_6 <-0.075)=0.943[/tex]

The p value for this case is lower than the significance level so then we have enough evidence to FAIL to reject the null hypothesis and we can conclude that the true mean is not significantly different from 51

Step-by-step explanation:

Info given

50, 53, 55, 43, 50, 47, 58.

We can calculate the sample mean and deviation with this formula:

[tex]\bar X=\frac{\sum_{i=1}^n X_i}{n}[/tex]

[tex]s=\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2)}{n-1}}[/tex]

represent the mean height for the sample  

[tex]s=5.014[/tex] represent the sample standard deviation for the sample  

[tex]n=7[/tex] sample size  

represent the value that we want to test

[tex]\alpha=0.05[/tex] represent the significance level for the hypothesis test.  

t would represent the statistic (variable of interest)  

[tex]p_v[/tex] represent the p value

Hypothesis to test

We want to test if the true mean is equal to 51, the system of hypothesis would be:  

Null hypothesis:[tex]\mu = 51[/tex]  

Alternative hypothesis:[tex]\mu \neq 51[/tex]  

The statistic is given by:

[tex]t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}[/tex]  (1)  

Replacing we got:

[tex]t=\frac{50.857-51}{\frac{5.014}{\sqrt{7}}}=-0.075[/tex]    

The degrees of freedom are given by:

[tex]df=n-1=7-1=6[/tex]  

The p value for this case would be given:

[tex]p_v = 2*P(t_6 <-0.075)=0.943[/tex]

The p value for this case is lower than the significance level so then we have enough evidence to FAIL to reject the null hypothesis and we can conclude that the true mean is not significantly different from 51

Answer:

Jill bought 16 books and Sam bought 9 books

Step-by-step explanation:

Let the number of books that Jill bought be j.

Let the number of books that Sam bought be s.

Jill bought 7 more books than Sam:

j = 7 + s

They bought 25 books altogether:

j + s = 25

Put j = 7 + s into the second equation:

7 + s + s = 25

7 + 2s = 25

2s = 25 - 7 = 18

s = 18/2 = 9 books

Therefore:

j = 7 + s = 7 + 9

s = 16 books

Jill bought 16 books and Sam bought 9 books.

is this what u need.....

Assuming the coin is not weighted and is a fair and standard coin - the chance of flipping head is 1/2. You can either flip head or tails, there are no other possible outcomes.

Answer:

[tex]\frac{1}{3}*(x-5)=\frac{-2}{3}[/tex]

Step-by-step explanation:

Let the number be x

Difference of a number & 5 : x-5

1/3 time the difference of a number & 5: 1/3 (x-5)

Equation:

[tex]\frac{1}{3}*(x-5)=\frac{-2}{3}[/tex]

Solution:

[tex]x-5=\frac{-2}{3}*\frac{3}{1}\\\\x-5=-2\\\\x=-2+5\\x=3[/tex]

Answer:

D) 86 – 18x – 8 = 12x + 18

X = 2

Step-by-step explanation:

86 – 2 (9x + 4) = 12x + 18

This question has a straight forward answer...

It's just to open up the bracket and ensure that the negative sign before the bracket multiply the values in the bracket exactly.

So opening up the bracket gives us this as the answer

86 - 18x -8 = 12x +18

86-18-8 = 12x+ 18x

60 = 30x

X = 2

Answer:

4 and 4

Step-by-step explanation:

We have 2 numbers that will be X and Y

X * Y = 16 => Y = 16 / X

We must minimize the sum, therefore:

S = X + Y

S = X + 16 / X

we derive and equal 0 and we are left with:

dS / dA = 1 - 16 / (X ^ 2) = 0

1 = 16 / X ^ 2

X ^ 2 = 16

X = 4

in the case of Y:

Y = 16/4 = 4

Therefore the numbers are 4 and 4.

The two positive numbers are 4 and 4

Let the two numbers be x and y

If the product of both numbers is 16, hence;

xy = 16 ........................... 1

If the sum will be at the minimum, hence x + y = minimum

From equation1, x = 16/ y

Substitute into the second equation to have;

16/y + y = A(y)

A(y) = 16/y + y

For the expression to be at a minimum, hence dA/dy = 0

dA/dy = -16/y² + 1

0 = -16/y² + 1

0 - 1 =  -16/y²

-y² = -16

y = √16

y = 4

Recall that xy = 16

4x= 16

x = 4

Hence the two positive numbers are 4 and 4

LEarn more here: https://brainly.com/question/13598452

Answer:

The  probability of a bulb lasting for at most 552 hours.

P(x>552)  = 0.0515

Step-by-step explanation:

Step(i):-

Given mean of the life time of a bulb = 510 hours

Standard deviation of the lifetime of a bulb = 25 hours

Let 'X' be the random variable in normal distribution

Let 'x' = 552

[tex]Z = \frac{x-mean}{S.D} = \frac{552-510}{25} =1.628[/tex]

Step(ii):-

The  probability of a bulb lasting for at most 552 hours.

P(x>552) = P(Z>1.63)

               = 1- P( Z< 1.63)

               =  1 - ( 0.5 + A(1.63)

              =   1- 0.5 - A(1.63)

              =   0.5 -A(1.63)

              =   0.5 -0.4485

             =  0.0515

Conclusion:-

The  probability of a bulb lasting for at most 552 hours.

P(x>552)  = 0.0515

Answer:

  A.  (2, 4)

Step-by-step explanation:

The ordered pairs represent (x, y). Since you have y =2x, this is the same as ...

  (x, 2x)

That is, the second number in the pair needs to be twice the first number in the pair. Since you know your times tables, you know that this is not the case for (1, 0), (10, 5) or (4, 12). Those values of x would give (1, 2), (10, 20), (4, 8).

It is the case that you have (x, 2x) for (2, 4).

The point (2, 4) lies on the graph of y = 2x.

Answer:

First choice

Step-by-step explanation:

Start by arranging the exponents of 10 in ascending order.

9.4 * 10^-8, 9.25 * 10^-6, 2.5 * 10^3, 7 * 10^3

The exponents are in ascending order, -8, -6, 3, 3

Since the last two exponents are equal, we must compare the numbers that multiply the powers of 10. They are 2.5 and 7. Since 2.5 < 7, ascending order is 2.5, 7. That means the line above is in ascending order.

Answer: First choice

Answer:

option 1

Step-by-step explanation:

[tex]r=\sqrt{(5\sqrt{2})^{2}+(-5\sqrt{2})^{2} } \\\\=\sqrt{25*2+25*2}\\\\ =\sqrt{50+50}\\\\=\sqrt{100}\\\\=10[/tex]

[tex]x=tan^{-1}(\frac{-5\sqrt{2}}{5\sqrt{2}})\\\\x=tan^{-1} (-1)\\x=\frac{7\pi}{4}[/tex]

[tex]re^{ix}=10e^{i\frac{7\pi}{4}}[/tex]

Answer:

8/25

Step-by-step explanation:

The probability of picking a number less than 9 is 4/5.

The probability of picking an even number is 2/5.

[tex]4/5 \times 2/5[/tex]

[tex]=8/25[/tex]

Answer: Anything above 2

Step-by-step explanation:

Answer: 3,4,5,6,7,8,9 (Any of these digits work)

Step-by-step explanation:

We want to find a digit that makes the number greater than 3260.2. There are many digits that can fit in there.

3318.7≥3260.2

Here, we plugged in a 3. that makes this sentence true because 3318.7 is greater than or equal to 3260.2. Since 3 works, we know that any digit greater than 3 would fit.

The question is incomplete! Complete question along with answer and step by step explanation is provided below.

Question:

The rectangle has an area of 60 square feet. Find its dimensions (in ft) if the length of the rectangle is 4 ft more than its widh.

smaller value ___________________ ft

larger value ____________________ ft

Answer:

Smaller value = 6 ft

Larger value = 10 ft

Step-by-step explanation:

Recall that the area of a rectangle is given by

[tex]Area = W \times L[/tex]

Where W is the width and L is the length of the rectangle.

It is given that the rectangle has an area of 60 square feet.

[tex]Area = 60 \: ft^2 \\\\60 = W \times L \\\\[/tex]

It is also given that the length of the rectangle is 4 ft more than its width

[tex]L = W + 4[/tex]

Substitute [tex]L = W + 4[/tex] into the above equation

[tex]60 = W \times (W + 4) \\\\60 = W^2 + 4W \\\\W^2 + 4W - 60 = 0 \\\\[/tex]

So we are left with a quadratic equation.

We may solve the quadratic equation using the factorization method  

[tex]W^2 + 10W - 6W - 60 \\\\W(W + 10) – 6(W + 10) \\\\(W + 10) (W - 6) = 0 \\\\[/tex]

So,

[tex](W + 10) = 0 \\\\W = -10 \\\\[/tex]

Since width cannot be negative, discard the negative value of W

[tex](W - 6) = 0 \\\\W = 6 \: ft \\\\[/tex]

The length of the rectangle is  

[tex]L = W + 4 \\\\L = 6 + 4 \\\\L = 10 \: ft \\\\[/tex]

Therefore, the dimensions of the rectangle are

Smaller value = 6 ft

Larger value = 10 ft

Verification:

[tex]Area = W \times L \\\\Area = 6 \times 10 \\\\Area = 60 \: ft^2 \\\\[/tex]

Hence verified.

Answer:

A digit that makes this sentence true is 4.

Step-by-step explanation:

Since the first digit in the number to the left is 3, you simply have to find a digit greater than 3. Here are the possibilities:

4

5

6

7

8

and

9

Out of any of these you can choose, I chose 4.

9514 1404 393

Answer:

   3, or any greater digit

Step-by-step explanation:

Suppose the digit is 'd'. Then the value on the right is ...

  69.436 +100d

Subtracting the value on the left, we want the difference greater than 0.

  69.436 +100d - 352.934 > 0

  100d -293.498 > 0 . . . . simplify

  100d > 293.498 . . . . . . . add 293.498

  d > 2.93498 . . . . . . . . . . divide by 100

That is d is any single digit greater than 2.9. Those digits are ...

  d ∈ {3, 4, 5, 6, 7, 8, 9}

Any digit 3 or greater makes the sentence true.

Answer:

A. f(x) = x^2 + 4x + 3

D. f(x) = -2x^2 - 8x + 1

Step-by-step explanation:

The axis of symmetry is found by h = -b/2a  where ax^2 +bx +c

A. f(x) = x^2 + 4x + 3

  h = -4/2*1 = -2    x=-2

B. f(x) = x^2 - 4x - 5

h = - -4/2*1 = 4/2 =2  x=2  not -2

C. f(x) = x^2 + 6x + 2

h =  -6/2*1 = -3/2 =  x=-3/2  not -2

D. f(x) = -2x^2 - 8x + 1

h = - -8/2*-2 = 8/-4 =-2  x=-2  

E. f(x) = -2x^2 + 8x - 2

h = - 8/2*-2 = -8/-4 =2  x=2  not -2

Answer:

Hey there! The answer to this question is

A. f(x) = x^2 + 4x + 3

D. f(x) = -2x^2 - 8x + 1

Answer:

1/8

Step-by-step explanation:

Total cards = 8

Card with 4 = 1

P(4) = 1/8

Answer:

I noticed a pattern:

3 * 2 + 6 = 12 and 2 * 2 + 5 = 9

This means that a*b = 2a + b.

Answer:

a. t>w

Step-by-step explanation:

Sin t= 0.29

t = sin^-1(0.29)

t= 16.86°

Sin w= 0.43

W = sin^-1(0.43)

W= 25.47°

Angles in the second quadrant are positive in sine and they are generally determined by subtracting the initial value from 180°

For t= 180°-16.86°

t = 163.14°

For w = 180°-25.47°

W= 154.53°

163.14°>154.53°

t>w

Answer:

Step-by-step explanation:

Volume of a hemisphere is given by

[tex]V = \frac{2}{3} \pi {r}^{3} [/tex]

where r is the radius of the hemisphere

From the question

r = 29 ft

Substitute the value of r into the formula

That's

[tex]V = \frac{2}{3} \pi \times {29}^{3} [/tex]

[tex]V = \frac{48778}{3} \pi[/tex]

We have the final answer as

Hope this helps you

Answer:

b) We are 90% confident that the mean salary of all CEOs in the electronics industry falls in the interval $139,048 to $154,144.

Step-by-step explanation:

Confidence interval:

Confidence level of x%

We build from a sample.

Between a and b.

Intepretation: We are x% sure that the population mean is between a and b.

In this question:

90%

45 CEO's

Between ($139,048, $154,144).

So

We are 90% sure that the mean salary of all CEO's falls within this interval.

The correct answer is:

b) We are 90% confident that the mean salary of all CEOs in the electronics industry falls in the interval $139,048 to $154,144.