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3 years ago

6

the amount of time a certain brand of light bulb lasts is normally distributed with a mean if 1800 hours and a standard deviatio

n of 85 hours. Using the empirical rule, what percentage of light bulbs last between 1630 hours and 1970 hours?

1 answer:

RUDIKE [14]3 years ago

4 0

Answer:

340%

Step-by-step explanation:

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3(x+4)=5(x-2) I really need help i have no idea how to do it

Oksana_A [137]

<u>answer:</u> $x = 11$

<u>work:</u>

$3(x+4)=5(x-2)$ | distribute 3 and 5 into the parentheses.

$3x + 12 = 5x - 10$ | subtract 5x and move it over to 3x, and solve.

$-2x + 12 = -10$ | subtract 12 and move it over to -10, and solve.

$-2x = -22$ | divide by -2.

$x = 11$ | final answer.

hope this helps! ❤ from peachimin

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3 years ago

Read 2 more answers

How do the lengths of the corresponding sides compare? How do you know?

ra1l [238]

Step-by-step explanation:

if two have the same shape, they are called "similar". When two figures are similar, the ratio of the lengths of their corresponding sides are equal. To determine if the triangles show are similar, compare their corresponding sides. Triangles ABC is similar to triangle DEF.

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3 years ago

The percent, X , of shrinkage o n drying for a certain type of plastic clay has an average shrinkage percentage :, where paramet

never [62]

Answer:

a) $t=\frac{18.4-17.5}{\frac{2.2}{\sqrt{45}}}=2.744$

The degrees of freedom are given by:

$df=n-1=45-1=44$

The critical value for this case is $t_{\alpha}=1.68$ since the calculated value is higher than the critical we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly higher than 18.4

b) $p_v =P(t_{(44)}>2.744)=0.0044$

Step-by-step explanation:

Information given

$\bar X=18.4$ represent the sample mean

$s=2.2$ represent the sample standard deviation

$n=45$ sample size

$\mu_o =17.5$ represent the value to verify

$\alpha=0.05$ represent the significance level

t would represent the statistic

$p_v$ represent the p value

Part a

We want to test if the true mean is higher than 17.5, the system of hypothesis would be:

Null hypothesis: $\mu \leq 17.5$

Alternative hypothesis: $\mu > 17.5$

The statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

And replacing we got:

$t=\frac{18.4-17.5}{\frac{2.2}{\sqrt{45}}}=2.744$

The degrees of freedom are given by:

$df=n-1=45-1=44$

The critical value for this case is $t_{\alpha}=1.68$ since the calculated value is higher than the critical we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly higher than 18.4

Part b

The p value would be given by:

$p_v =P(t_{(44)}>2.744)=0.0044$

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3 years ago

What is the rule and the missing number? <br> 5, , 10,12 1/2 , …

Neko [114]

7 1/2 the rule is add two and a half: +2 1/2

6 0

4 years ago

The sum of the measures of angles for a triangle is 180°. Find the value of x and then the measures of the 3 angles

dmitriy555 [2]

Answer:

The value of x is 50

The measures of the 3 angles are 50°, 100°, 30°

Step-by-step explanation:

Let us solve the question

∵ The sum of the measures of the angles of a triangle is 180°

∵ The measures of the 3 angles of the given Δ are x°, 2x°, (x - 20)°

→ Add them and equate the sum by 180

∴ x° + 2x° + (x - 20)° = 180°

→ Add the like terms

∵ (x + 2x + x) + (-20) = 180

∴ 4x - 20 = 180

→ Add 20 to both sides

∵ 4x - 20 + 20 = 180 + 20

∴ 4x = 200

→ Divide both sides by 4 to find x

∴ x = 50

∴ The value of x is 50

To find the measures of the 3 angles substitute x by 50 in their expressions

∵ The measure of one angle is x

∴ The measure of the 1st angle is 50°

∵ The measure of the 2nd angle is 2x

∴ The measure of the 2nd angle = 2(50)

∴ The measure of the 2nd angle is 100°

∵ The measure of the 3rd angle is (x - 20)

∴ The measure of the 3rd angle = (50 - 20)

∴ The measure of the 3rd angle is 30°

∴ The measures of the 3 angles are 50°, 100°, 30°

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3 years ago