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klio [65]
3 years ago
8

The maintenance department at the main campus of a large state university receives daily requests to replace fluorecent lightbul

bs. The distribution of the number of daily requests is bell-shaped and has a mean of 40 and a standard deviation of 4. Using the 68-95-99.7 rule, what is the approximate percentage of lightbulb replacement requests numbering between 40 and 48?

Mathematics
1 answer:
aliina [53]3 years ago
7 0

Answer: 47.5%

Step-by-step explanation:

Given : The distribution of the number of daily requests is bell-shaped and has a mean of \mu=40 and a standard deviation of 40\sigma=4.

To find : The approximate percentage of lightbulb replacement requests numbering between 40 and 48.

We can see that 48=40+2(4) i.e. 48 is two standard deviations ( to the right) from the mean.               (1)

And 40 is the mean value (\mu) itself . It means the lower limit lies at the center of the normal curve (at z=0).

It means we need only right the region which is 2 standard deviations from the mean (at z=2).

According to the 68-95-99.7 rule, 95% of the population falls within two deviation from the mean in both left and right side of the normal curve.

Then, the required area will be : \dfrac{95\%}{2}=47.5\%

Hence,  the approximate percentage of lightbulb replacement requests numbering between 40 and 48 = 47.5%

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Using the formula C=2pi r find the circumference of a circle with diameter of 28 inches. Round your answer to the nearest inch.
Ivenika [448]

Answer: 88 inches

Step-by-step explanation:

We know that the formula to find the circumference of circle is given by :-

C=2\pi r, where r is the radius of the circle.

Given : Diameter of circle = 28 inches

Also, diameter is twice of radius.

i.e. 2r=28

Therefore, the circumference of circle will be :-

C=2\pi r=(2r)\pi=28\times(3.14)=87.92text{ inches}\approx88\text{ inches}

Hence, the  circumference of circle is 88 inches.

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3 years ago
What is the approximate area of this figure?A.25 cmB.29 cmC.38 cmD.42 cm
amm1812

Answer:

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Step-by-step explanation:

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2 years ago
Which is bigger, 7/8 or 9/10
Nonamiya [84]
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7 0
3 years ago
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Ghella [55]
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Read 2 more answers
Can someone finish the whole thing ??
Romashka-Z-Leto [24]
<h3>Answer:    y = (3/2)x + 0</h3>

This is the same as  y = (3/2)x

=============================================================

Work Shown:

Find the slope of the line through (x1,y1) = (-2,-3) and (x2,y2) = (2,3)

m = (y2 - y1)/(x2 - x1)

m = (3 - (-3))/(2 - (-2))

m = (3 + 3)/(2 + 2)

m = 6/4

m = 3/2

The slope is the fraction 3/2. This is going to be in front of the x, or to the left of the x.

----------

Plug m = 3/2 and (x1,y1) = (-2,-3) into the point slope formula. Solve for y.

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y + 3 = (3/2)x + (3/2)(2)

y + 3 = (3/2)*x + 3

y + 3 - 3 = (3/2)*x + 3 - 3

y = (3/2)x + 0

The y intercept is zero. This matches up with the fact the graph crosses the y axis at y = 0.

3 0
3 years ago
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