Answer:
The volume of the ball with the drilled hole is:
Step-by-step explanation:
See attached a sketch of the region that is revolved about the y-axis to produce the upper half of the ball. Notice the function y is the equation of a circle centered at the origin with radius 15:
Then we set the integral for the volume by using shell method:
That can be solved by substitution:
The limits of integration also change:
For x=5: 
For x=15: 
So the integral becomes:
If we flip the limits we also get rid of the minus in front, and writing the root as an exponent we get:
Then applying the basic rule we get:
Since that is just half of the solid, we multiply by 2 to get the complete volume:
To solve for proportion we make use of the z statistic.
The procedure is to solve for the value of the z score and then locate for the
proportion using the standard distribution tables. The formula for z score is:
z = (X – μ) / σ
where X is the sample value, μ is the mean value and σ is
the standard deviation
when X = 70
z1 = (70 – 100) / 15 = -2
Using the standard distribution tables, proportion is P1
= 0.0228
when X = 130
z2 = (130 – 100) /15 = 2
Using the standard distribution tables, proportion is P2
= 0.9772
Therefore the proportion between X of 70 and 130 is:
P (70<X<130) = P2 – P1
P (70<X<130) = 0.9772 - 0.0228
P (70<X<130) = 0.9544
Therefore 0.9544 or 95.44% of the test takers scored
between 70 and 130.
Answer:
25 cm
Step-by-step explanation:
The last selection should be your answer
