Can somebody please help? It would be very appreciated. C:

Step-by-step explanation:

Let x be the number of 10 cent coins

Let y be the number of 20 cent coins

given

[tex]x = y + 12 \\ x - y = 12[/tex]

as equation 1

and

[tex]0.1x + 0.2y = 5.4[/tex]

as equation 2.

Now we will use elimination method to solve simultaneous equations.

Now we multiply equation 1 by 0.2 to eliminate y and solve for x first.

[tex]0.2 \times x - 0.2 \times y = 12 \times 0.2 \\ 0.2x - 0.2y = 2.4[/tex]

Let this new equation be equation 3.

Now use equation 2 + equation 3.

[tex]0.1x + 0.2x + (0.2y + ( - 0.2y)) = 5.4 + 2.4 \\ 0.3x = 7.8 \\ x = 7.8 \div 0.3 \\ = 26[/tex]

Substitute x into equation 1,

[tex]x = y + 12 \\ y + 12 = x \\ y = x - 12 \\ = 26 - 12 \\ = 14[/tex]

Therefore total number of coins = x + y = 26 + 14 = 40

Answer:

in total he has 62 cents

Step-by-step explanation:

I hope it's the correct answer if I'm wrong tell me right away.

Answer:

I would say to look on alpha calculator to get any help if anyone dosent answer this!!

Step-by-step explanation:

Answer:

The distance across Africa would be measured in kilometers, and the height of a swingset would be in meters.

Step-by-step explanation:

Kilometers is larger than all of the other ones and Africa is across the ocean

A swingset isn't extremely tall but not short

Answer:

a) By the Central Limit Theorem, it is approximately normal.

b) The standard error of the distribution of the sample mean is 1.8333.

c) 0.1379 = 13.79% of the samples will have a mean useful life of more than 38 hours.

d) 0.7939 = 79.39% of the samples will have a mean useful life greater than 34.5 hours

e) 0.656 = 65.6% of the samples will have a mean useful life between 34.5 and 38 hours

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 [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score 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 p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

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

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

Mean of 36 hours and a standard deviation of 5.5 hours.

This means that [tex]\mu = 36, \sigma = 5.5[/tex]

a. What can you say about the shape of the distribution of the sample mean?

By the Central Limit Theorem, it is approximately normal.

b. What is the standard error of the distribution of the sample mean? (Round your answer to 4 decimal places.)

Sample of 9 means that [tex]n = 9[/tex]. So

[tex]s = \frac{\sigma}{\sqrt{n}} = \frac{5.5}{\sqrt{9}} = 1.8333[/tex]

The standard error of the distribution of the sample mean is 1.8333.

c. What proportion of the samples will have a mean useful life of more than 38 hours?

This is 1 subtracted by the pvalue of Z when X = 38. So

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

By the Central Limit Theorem

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

[tex]Z = \frac{38 - 36}{1.8333}[/tex]

[tex]Z = 1.09[/tex]

[tex]Z = 1.09[/tex] has a pvalue of 0.8621

1 - 0.8621 = 0.1379

0.1379 = 13.79% of the samples will have a mean useful life of more than 38 hours.

d. What proportion of the sample will have a mean useful life greater than 34.5 hours?

This is 1 subtracted by the pvalue of Z when X = 34.5. So

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

[tex]Z = \frac{34.5 - 36}{1.8333}[/tex]

[tex]Z = -0.82[/tex]

[tex]Z = -0.82[/tex] has a pvalue of 0.2061.

1 - 0.2061 = 0.7939

0.7939 = 79.39% of the samples will have a mean useful life greater than 34.5 hours.

e. What proportion of the sample will have a mean useful life between 34.5 and 38 hours?

pvalue of Z when X = 38 subtracted by the pvalue of Z when X = 34.5. So

0.8621 - 0.2061 = 0.656

0.656 = 65.6% of the samples will have a mean useful life between 34.5 and 38 hours

Answer:

d. D: (-∞ , ∞) , R: (-10 , ∞)

Step-by-step explanation:

Answer:

D. - 1/4

Step-by-step explanation:

Answer:

3sqrt(2) ................

Answer:

0.047

Step-by-step explanation:

The computation of the probability is shown below:

P(dying) = 1 ÷ 150

So,

P(living) = 149 ÷ 150

As There are 120 women.

Now

P(x>=3) = 1 - [P(x=0) + P(x=1) + P(x=2)]

= 1 -[(120 = 0)((1 ÷ 150)^0)((149 ÷ 150)^120) + (120 = 1)((1 ÷ 150)^1)((149 ÷ 150)^119) + (120 = 2)((1 ÷ 150)^2)((149 ÷150)^118)]

P(x>=3)

=0.047

Answer:

obtuse it is more than 90 so not a right and a straight angles is 180 degrees so it obtuse

Answer:

Explain what?? May I ask

9514 1404 393

Answer:

  C.  13  —  your choice is correct

Step-by-step explanation:

The part of A that is outside of B is the region identified as I. It has a population of 13, as you have marked.

  AB' = 13

Answer:

B

Step-by-step explanation:

Answer:

<x=22.02431284 degrees

Step-by-step explanation:

sin(x)=3/8

sin^-1(3/8)=<x

<x=22.02431284 degrees

Answer:

2nd option

Step-by-step explanation:

Answer:

We expect 95% of head breadths to be between 4.3 inches and 7.5 inches.

Step-by-step explanation:

The Empirical Rule states that, for a normally distributed random variable:

Approximately 68% of the measures are within 1 standard deviation of the mean.

Approximately 95% of the measures are within 2 standard deviations of the mean.

Approximately 99.7% of the measures are within 3 standard deviations of the mean.

In this problem, we have that:

Mean = 5.9 inches, standard deviation = 0.8 inches.

We expect 95% of head breadths to be between

Within 2 standard deviations of the mean, so:

5.9 - 2*0.8 = 5.9 - 1.6 = 4.3 inches

5.9 + 2*0.8 = 5.9 + 1.6 = 7.5 inches

We expect 95% of head breadths to be between 4.3 inches and 7.5 inches.

Answer: 30 & 40

Step-by-step explanation:

Answer:

hope it helps...

Step-by-step explanation:

Answer:

f(x+2) = 3(x+2)^2 + 2(x+2) + 1

Step-by-step explanation:

Replace x with x+2 and you get the solution above. Hope this helps!

Answer:

The intermediate step is determining what a is, knowing also that (x+a)²=x²+(2a)x+a².

Also, x²-16x= -68 (in the form (x+a)²=b) is (x-8)²=-4

Step-by-step explanation:

x²-16x=-68

x²-16x+68=0

I suppose the intermediate step is finding (x+a)².

Remember that (x+a)²=x²+(2a)x+a², so 'a' will be half the coefficient of x (number beside x, not x²). The coefficient of x here is -16, so a is -8.

(x-8)²=x²-16x+64

So, if we can create 'x²-16x+64' out of 'x²-16x+68', we'll be on our way:

x²-16x+68=0

(x²-16x+64)+4=0

(x-8)²+4=0

(x-8)²=-4

Answer:

Yes.  The city has a lower proportion of accidents by 16-year-old male drivers than the national proportion (16.7% compared to 21%).

Step-by-step explanation:

a) Data and Calculations:

Number of 16-year-old males involved in driver accident during year 2000 = 210

Sample number of drivers = 1,000

National rate of accidents for 16-year-old males for every 1,000 drivers = 21% (210/1,000 * 100)

Random sample of 16-year-old male drivers in a Midwest city = 150

Number of them involved in driver-accidents = 25

Proportion of 16-year-old males involved in driver-accidents = 25/150 * 100 = 16.7%

The city's 16.7% proportion is lower than the national proportion of 21%.

9514 1404 393

Answer:

  405 mph; 325 mph

Step-by-step explanation:

The total of their speeds is ...

  2920 mi/(4 h) = 730 mi/h

If s represents the speed of the slower plane, then we have ...

  s + (s+80) = 730

  2s = 650 . . . . . . .  subtract 80

  s = 325 . . . . . . . divide by 2

  s+80 = 405 . . .  find the faster speed

The speeds of the planes are 405 mi/h and 325 mi/h.

Answer:

18/35....

....

YESTERDAY

Answer:

two points in the xy plane has cartesian coordinate (2,-4) and (-3,3) where the units are in m determine.

a) the distance between these points and

b) their polar coordinates.

Answer:

[tex] {a}^{3} - {b}^{3} [/tex]

[tex] = (a - b)( {a}^{2} + ab + {b}^{2} )[/tex]

Hence, simplified.

Answer:

B. y = 3x - 14

Step-by-step explanation:

Since the line is parallel, your slope will be 3. You're given a point, so you can use point-slope form to find the equation. Point-slope form is:

y - y1 = m(x - x1) where (x1, y1) is the point that they gave you and m is the slope. So:

y - (-2) = 3(x - 4) --> Start to simplify this by changing - (-2) to +2 and distributing the 3 to (x - 4).

y + 2 = 3x - 12 --> Subtract 2 from both sides.

y = 3x - 14

Answer:

C

Step-by-step explanation:

A is just the opposite value of the second integral.

B is just 3 times the first.

D-you can write a sum of integrals over the same intervals as one integral of the sum of the integrands of those integrals over that same interval. The answer would be 3(8)+-2.

For choice C, we would need more information.