4x - 2y =7 X +2y =3 What is x and y ??
1 answer:
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Answer:
And if we solve for a we got
So the value of height that separates the bottom 20% of data from the top 80% is 23.432.
Step-by-step explanation:
Let X the random variable that represent the heights of a population, and for this case we know the distribution for X is given by:
Where and
For this part we want to find a value a, such that we satisfy this condition:
(a)
(b)
As we can see on the figure attached the z value that satisfy the condition with 0.20 of the area on the left and 0.80 of the area on the right it's z=-0.842
If we use condition (b) from previous we have this:
But we know which value of z satisfy the previous equation so then we can do this:
And if we solve for a we got
So the value of height that separates the bottom 20% of data from the top 80% is 23.432.
Answer:
38 degrees
Step-by-step explanation:
By the Law of Cosines,
5² = 3² + 7² - 2(3)(7) cos A
5² - 3² - 7² = -2(3)(7) cos A
-33 = -42 cos A
cos A = 33/42
A = arccos(33/42), which is about 38 degrees.
