Answer:
A. E(x) = 1/n×n(n+1)/2
B. E(x²) = 1/n
Step-by-step explanation:
The n candidates for a job have been ranked 1,2,3....n. Let x be the rank of a randomly selected candidate. Therefore, the PMF of X is given as
P(x) = {1/n, x = 1,2...n}
Therefore,
Expectation of X
E(x) = summation {xP(×)}
= summation {X×1/n}
= 1/n summation{x}
= 1/n×n(n+1)/2
= n+1/2
Thus, E(x) = 1/n×n(n+1)/2
Value of E(x²)
E(x²) = summation {x²P(×)}
= summation{x²×1/n}
= 1/n
The perimeter of a shape is the sum of the lengths of its sides.
So, to find the perimeter of this quadrilateral, all we have to do is add the side lengths and simplify.
(x² - 6) + (2x + 5) + (x² - 3x) + (4x² + 2x)
x² + x² + 4x² + (-3x) + 2x + 2x + (-6) + 5
6x² + (-3x) + 2x + 2x + (-6) + 5
6x² + x + (-6) + 5
6x² + x + (-1)
6x² + x - 1
So, the perimeter of the quadrilateral is the quantity (6x² + x - 1).
Hope this helps!
To find the perpendicular line a y- 2 = 7/3 (x + 5) you must first observe that the slope is m = 7/3, therefore, the slope of the perpendicular line put of the reciprocal, that is, m = - 3/7. So the possible options are A or C, but since the point (-4, 9) must go through the line, we find that the equation that satisfies that is option C.Therefore the perpendicular line that passes through the point (-4, 9) is C. y - 9 = -3/7 (x + 4)
Answer:
Tauren has 78 keychains
James has 34 keychains
Marcus has 68 keychains
Yahya has 74 keychains
Step-by-step explanation:
I got this answer by doing this:
If Tauren has 78 keychains then its gonna be left like that.
If everybody else has an average of 68 keychains then divide 68 by 2 to get half of what marcus has which equals 34.
Then add the amount of James and marcus keychains which is 68 plus 34 which equals 102, the subtract the 28 because it says Yayha has 28 fewer keychains and that equals 74.
