Combine the like terms. Simplify your answer<br> -5m+2m

Joe went to the hobby shop and bought 2 model sports cars at $8.95 each and some paints. If he spent a total of $23.65, what was

Nostrana [21]

We have 2 cars at $8.85 each. So we have 8.85 * 2 = $17.70

If we know he spent 23.65, we can do 23.65 - 17.70 = 5.95

So the paint must have cost $5.95.

3 0

3 years ago

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A math teacher randomly selects one student in a class to write a probability question on a chalkboard. The teacher then randoml

Fittoniya [83]

Answer:

The probability to the nearest thousandth is 0.386

Step-by-step explanation:

Firstly, we will need to know the number of girls and the total number of students in the class.

We have the ratio as 3:5 for boys and girls with the number of boys being 18

What we have is thus;

3:5 = 18:g

3/5 = 18/g

3g = 90

g = 90/3

g = 30 girls

Thus, we have 18 boys and 30 girls with a total of 48 students.

The probability that the teacher selects a girl to write the question on the board is 30/48 = 5/8

Now, we intend selecting another girl to answer the question. This is like a probability without replacement. So this means that the number of girls we have now is 29 and the number of students we are selecting from is 47 students

Thus, the probability of selecting a girl to answer the question becomes 29/47

The joint probability is thus; 29/47 * 5/8 = 145/376 = 0.3856

To the nearest thousandth, we have 0.386

5 0

3 years ago

A hobby store is having a sale on picture frames buy 3 get the 4th one at 75% off. What is an expression to represent total cost

Contact [7]

A hobby store is having a sale on picture frames buy 3 get the 4th one at 75% off. What is an expression to represent total cost of 4 frames.

7 0

3 years ago

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The radius of a circle is 10. Using π, which equation expresses the ratio of the circumference of the circle to the circle's dia

Liula [17]

Answer:

π = C / d

Step-by-step explanation:

The circumference of a circle is given by the general formula;

C = 2 * π * r .... or C = π d (r = radius, d = diameter)

We can easily modify the second formula to isolate π in order to express the circumference in relation to the diameter:

π = C / d

To obtain π, you need to divide the circumference by the diameter.

We're used to think about the circumference in terms of radius... but since we deal with 2 * r * π and that 2 * r = d... it's also convenient to use the diameter.

6 0

3 years ago

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Refer to the random sample of customer order totals with an average of $78.25 and a population standard deviation of $22.50. a.

zysi [14]

Answer:

a) $78.25- 1.64 \frac{22.50}{\sqrt{40}}= 72.416$

$78.25+ 1.64 \frac{22.50}{\sqrt{40}}= 84.084$

b) $78.25- 1.64 \frac{22.50}{\sqrt{75}}= 73.989$

$78.25+ 1.64 \frac{22.50}{\sqrt{75}}= 82.511$

c) For this case when we increase the sample size the margin of error would be lower and then the interval would be narrower

d) $ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)

Solving for n we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

And replacing the info we have:

$n=(\frac{1.640(22.50)}{5})^2 =54.46 \approx 55$

Step-by-step explanation:

Part a

For this case we have the following data given

$\bar X = 78.25$ represent the sample mean for the customer order totals

$\sigma =22.50$ represent the population deviation

$n= 40$ represent the sample size selected

The confidence level is 90% or 0.90 and the significance level would be $\alpha=0.1$ and $\alpha/2 = 0.05$ and the critical value from the normal standard distirbution would be given by:

$z_{\alpha/2}=1.64$

And the confidence interval is given by:

$\bar X -z_{\alpha/2} \frac{\sigma}{\sqrt{n}}$

And replacing we got:

$78.25- 1.64 \frac{22.50}{\sqrt{40}}= 72.416$

$78.25+ 1.64 \frac{22.50}{\sqrt{40}}= 84.084$

Part b

The sample size is now n = 75, but the same confidence so the new interval would be:

$78.25- 1.64 \frac{22.50}{\sqrt{75}}= 73.989$

$78.25+ 1.64 \frac{22.50}{\sqrt{75}}= 82.511$

Part c

For this case when we increase the sample size the margin of error would be lower and then the interval would be narrower

Part d

The margin of error is given by:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)

Solving for n we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

And replacing the info we have:

$n=(\frac{1.640(22.50)}{5})^2 =54.46 \approx 55$

3 0

3 years ago

Combine the like terms. Simplify your answer -5m+2m