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3 years ago

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Three years ago, sharon was (8+b) years old and nora was (2b-1) years old. Lupe will be 3b years old in 2 years. Write an expres

sion in simplest form for the present day sum of the three girls' ages?

1 answer:

Usimov [2.4K]3 years ago

5 0

Answer:

Three years ago

S = 8 + b

N = 2b - 1

In two years

L = 3b

Add 3 to the first 2 expressions and minus 2 from the second

11 + b + 2b + 2 + 3b - 2

11 + 2 - 2 + b + 2b + 3b

11 + 6b

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Question 28 (1 point)

aniked [119]

Answer:

+ 16

Step-by-step explanation:

x² - 8x = - 10

to complete the square

add ( half the coefficient of the x- term )² to both sides

x² + 2(- 4)x + (- 4) = - 10 + (- 4)²

x² - 8x + 16 = - 10 + 16

thus 16 is added to both sides to complete the square

4 0

2 years ago

The sugar content of the syrup in canned peaches is normally distributed. A random sample of n = 10 cans yields a sample standar

Serggg [28]

Answer:

The 95% confidence interval is given by:

3.30<σ<8.76

Step-by-step explanation:

1) Data given and notation

s=4.798 represent the sample standard deviation

$\bar x$ represent the sample mean

n=10 the sample size

Confidence=95% or 0.95

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

The Chi Square distribution is the distribution of the sum of squared standard normal deviates .

2) Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=10-1=9$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a tabel to find the critical values.

The excel commands would be: "=CHISQ.INV(0.025,9)" "=CHISQ.INV(0.975,9)". so for this case the critical values are:

$\chi^2_{\alpha/2}=19.022$

$\chi^2_{1- \alpha/2}=2.700$

And replacing into the formula for the interval we got:

$\frac{(9)(4.798)^2}{19.022} \leq \sigma \frac{(9)(4.798)^2}{2.700}$

$10.892 \leq \sigma^2 \leq 76.736$

Now we just take square root on both sides of the interval and we got:

$3.30 \leq \sigma \leq 8.76$

So the best option would be:

3.30<σ<8.76

7 0

3 years ago

What multiplication fact can you double to find 4x7

AnnZ [28]

You can do subtract half of 4 which is 2 and multiply by 2 by 7 so it will be 2x14 which is the same thing as 7x4<span />

5 0

3 years ago

Read 2 more answers

What is the median of the data?

eimsori [14]

<span>20, 19, 13, 23, 16, 15, 17, 17, 15, 15, 22, 19

</span>To find the Median, place the numbers in value order<span> and find the </span>middle<span>.
</span>
13, 15, 15, 15, 16, 17, 17, 19, 19, 20, 22, 23

There are 12 numbers and so we don't have just one middle number, we have a pair of middle numbers:

13, 15, 15, 15, 16, (17, 17), 19, 19, 20, 22, 23

<span>To find the value halfway between them, add them together and divide by 2:
</span>
17 + 17 = 34
34 ÷ 2 = 17

So the median is A) 17.

8 0

3 years ago

Volume of 29 mL and has a mass of 53 g what’s is the density

RSB [31]

Answer: 1.82

Step-by-step explanation:

Density = $\frac{mass}{volume}$ *Divide the mass by volume.

= 1.82

8 0

3 years ago