Can someone help for my math test? its 20 points and ill be giving brainiest!
2 answers:
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<h3>Answer: 83.85%</h3>
This value is approximate.
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Explanation:
Let's compute the z score for x = 40
z = (x-mu)/sigma
z = (40-47)/7
z = -1
We're exactly one standard deviation below the mean.
Repeat these steps for x = 68
z = (x-mu)/sigma
z = (68-47)/7
z = 3
This score is exactly three standard deviations above the mean.
Now refer to the Empirical Rule chart below. We'll add up the percentages that are between z = -1 and z = 3. This consists of the two pink regions (each 34%), the right blue region (13.5%) and the right green region (2.35%). These percentages are approximate.
34+34+13.5+2.35 = 83.85
<u>Roughly 83.85%</u> of the one-mile roadways have between 40 and 68 potholes.
Answer:
The correct answer B) The volumes are equal.
Step-by-step explanation:
The area of a disk of revolution at any x about the x- axis is πy² where y=2x. If we integrate this area on the given range of values of x from x=0 to x=1 , we will get the volume of revolution about the x-axis, which here equals,
which when evaluated gives 4pi/3.
Now we have to calculate the volume of revolution about the y-axis. For that we have to first see by drawing the diagram that the area of the CD like disk centered about the y-axis for any y, as we rotate the triangular area given in the question would be pi - pi*x². if we integrate this area over the range of value of y that is from y=0 to y=2 , we will obtain the volume of revolution about the y-axis, which is given by,
If we just evaluate the integral as usual we will get 4pi/3 again(In the second step i have just replaced x with y/2 as given by the equation of the line), which is the same answer we got for the volume of revolution about the x-axis. Which means that the answer B) is correct.