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grandymaker [24]
3 years ago
13

What is 42 decreased by twice some number

Mathematics
1 answer:
harina [27]3 years ago
5 0
Well 42 divided by 2 is 21. than to double check you can do 21 plus 21 equals 42.
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Simplify the following expression using the distributive property: -8(2x - 5)
Misha Larkins [42]

Answer:

(B)-16+40

Step-by-step explanation: -8(2x-5)

-8*2=-16

-8*-5=40(positive because a negative multiplied by a negative is postive)

add the x to the answers...Then its -16x+40

Hope This Helps:)

5 0
3 years ago
3(x + 1) - (x-3) = 12<br> I need help I don’t I understand
balandron [24]

Answer:

3

Step-by-step explanation:

3x+3-x+3=12

3x-x=12-3-3

2x=6

x=6/2

x=3

4 0
3 years ago
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The owner of Matt’s Gas Station wants to study gasoline purchases of customers at his station. In 2017, the mean amount of gas
gulaghasi [49]

Answer:

Step-by-step explanation:

a) 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,

µ = 9

For the alternative hypothesis,

µ ≠ 9

This is a 2 tailed test

Since the population standard deviation is given, z score would be determined from the normal distribution table. The formula is

z = (x - µ)/(σ/√n)

Where

x = sample mean

µ = population mean

σ = population standard deviation

n = number of samples

From the information given,

µ = 9

x = 9.9

σ = 2.5

n = 50

z = (9.9 - 9)/(2.5/√50) = 2.55

Looking at the normal distribution table, the probability corresponding to the area above the z score is 1 - 0.99461 = 0.00539

Recall, population mean is 9

The difference between sample sample mean and population mean is 9.9 - 9 = 0.9

Since the curve is symmetrical and it is a two tailed test, the x value for the left tail is 9 - 0.9 = 8.1

the x value for the right tail is 9 + 0.9 = 9.9

These means are higher and lower than the null mean. Thus, they are evidence in favour of the alternative hypothesis. We will look at the area in both tails. Since it is showing in one tail only, we would double the area. We already got the area above the z score as z = 0.00539

We would double this area to include the area in the left tail of z = - 2.55. Thus

p = 0.00539 × 2 = 0.01078

Since alpha, 0.01 < 0.01078, we would reject the null hypothesis

But we are told to use the critical value approach, then

Since α = 0.01, the critical value is determined from the normal distribution table.

For the left, α/2 = 0.01/2 = 0.005

The z score for an area to the left of 0.005 is - 2.575

For the right, α/2 = 1 - 0.005 = 0.995

The z score for an area to the right of 0.995 is 2.575

In order to reject the null hypothesis, the test statistic must be smaller than - 2.575 or greater than 2.575

Since - 2.55 > - 2.575 and 2.55 < 2.575, we would reject the null hypothesis. This corresponds to our previous decision.

b) we would assume normal distribution because the sample size is sufficiently large and the population standard deviation is known.

c) Confidence interval is written in the form,

(Sample mean ± margin of error)

Since the sample size is large and the population standard deviation is known, we would use the following formula and determine the z score from the normal distribution table.

Margin of error = z × σ/√n

The z score for confidence level of 99% is 2.58

Margin of error = 2.58 × 2.5/√50 = 0.91

Confidence interval = 9.9 ± 0.91

The lower end of the confidence interval is

9.9 - 0.91 = 8.99

Therefore, p = 9 will be contained in the interval.

4 0
3 years ago
An Account grows at an annual interest rate, it grows by a factor of x=1 + r each year. The function A(x)=800x^4 + 350x^3 + 500x
Marina86 [1]

Answer:

Applying the formula, it is found that the total amount in the account will be of $2,431.3. I THINK

Step-by-step explanation:

IM NOT SURE!

7 0
2 years ago
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A commercial builder has a downtown lot with 250 frontage feet on Broadway. The lot is 200’ deep. By code, the builder must allo
Morgarella [4.7K]

Subtract 15 from the depth:

200-15 = 185

Subtract 20 from the width ( 10 from both sides)

250-20 = 230

Area to build on: 185 x 230 = 42,550 square feet.

8 0
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