Answer:
62.17% probability that a randomly selected exam will require more than 15 minutes to grade
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:

What is the probability that a randomly selected exam will require more than 15 minutes to grade
This is 1 subtracted by the pvalue of Z when X = 15. So



has a pvalue of 0.3783.
1 - 0.3783 = 0.6217
62.17% probability that a randomly selected exam will require more than 15 minutes to grade
The way I like to figure out problems like this is to write it out like,
1/10 = x/6000
(One over ten equals x over 6000)
Then you find out how much you multiplied 10 by to get 6000. To do this you can divide 6000 by 10 getting 600. The rule "what you do to the bottom you have to do to top" in this equation. So since you multiplied the bottom by 600 you have to multiply the top by 600 as well. 600 times 1 is just 600.
So your answer is, 600 is 1/10 of 6000.
Hope this helps and isn't too confusing.
Answer: 
Step-by-step explanation:
1. If you join the top part and the bottom part of the figure, you obtain a sphere. Then, you must apply the formula for calculate the surface area of a sphere:

Where r is the radius (
)
2. Then:

3. The formula for calculate the suface area of the red part, which is a cylinder, is:

Where h is the height (h=32mm)
4. Then:

5. So, the total surface area is:

Equation 1) 4x + 2y = 8
Equation 2) 16x - y = 14
Multiply all of equation 2 by 2.
2) 2(16x - y = 14)
2) 32x - 2y = 28
1) 4x + 2y = 8
Add equations together.
36x = 36
Divide both sides by 36.
x = 1
Plug in 1 for x in the first equation.
4x + 2y = 8
4(1) + 2y = 8
4 + 2y = 8
Subtract 4 from both sides.
2y = 8 - 4
2y = 4
Divide both sides by 2.
y = 4/2
y = 2
So, x = 1, y = 2
~Hope I helped!~