stacey and Neil painted 280 ft2 of their living room wall with 4/5 gallons of paint. How many square feet can they paint with 3
2 answers:
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Answer:
Step-by-step explanation:
We need to use z-scores and a standard normal table to find the values that corresponds to the probabilities given, and then to solve a system of equations to find .
For finding probabilities that corresponds to z-scores, we are going to use here a <u>Standard Normal Table </u><u><em>for cumulative probabilities from the mean </em></u><em>(Standard normal table. Cumulative from the mean (0 to Z), 2020, in Wikipedia) </em>that is, the "probability that a statistic is between 0 (the mean) and Z".
A value of a z-score for the probability P(100<x<mean) = 22.57% = 0.2257 corresponds to a value of z-score = 0.6, that is, the value is 0.6 standard deviations from the mean. Since this value is <em>below the mean</em> ("the items produced weigh between 100 grams up to the mean"), then the z-score is negative.
Then
(1)
We can apply the same procedure as before. A value of a z-score for the probability P(mean<x<190) = 49.18% = 0.4918 corresponds to a value of z-score = 2.4, which is positive since it is after the mean.
Then
(2)
Having equations (1) and (2), we can form a system of two equations and two unknowns values:
(1)
(2)
Rearranging these two equations:
(1)
(2)
To solve this system of equations, we can multiply (1) by -1, and them sum the two resulting equation:
(1)
(2)
Summing both equations, we obtain the following equation:
Then
To find the value of the mean, we need to substitute the value obtained for the standard deviation in equation (2):
(2)
Answer with Step-by-step explanation:
Let Z be a set of integers
We have to prove that is odd for all value of x
Z.
There are two cases
1.When x is an odd integer number
2.when x is even integer number
1.When x is an odd integer number
When x is positive odd integer
Then is positive odd number (because square of odd positive number is always positive an odd number )
5x is also odd number
-5x -1 = -even number
Suppose x=3
Then -15-1=-16
Odd number - even number=Odd number
Hence , is an odd number .
When x is negative odd number
Then x square is positive odd number and 5x is negative odd term term
Therefore,odd number + odd number -1=Even number -1=Odd number
Hence is an odd number.
2.When x is an even number
When x is positive even number
x square is positive even number and 5x is positive even number
Even number -Even number -1 =Even number -odd number =Odd number
Suppose x=4
=16-20-1=-5=Odd number
When x is negative even number
Then x square is positive even number and 5x is negative even number
=Even number +Even number -1=Even number -1=Odd number
Hence, for all elements of Zis odd.