<span>x> -4 means that it is needed to find all the values that are greater than -4 "not including" -4 ... for negative values as you get from zero the values decrease which means that -8 is less than -7 and -7 is less than -6 etc.. and positive values are trivially known to be greater than negative ones then take each value and compare it with -4 -8 is less than -4 -4.3 is less than -4 -4 is equal to -4 which is not included in our required range which is x>-4 -3.8 is greater than -4 which will get in our solution 1.2 is greater than -4 3 is also greater than -4 So our final solution will be {-3.8,1.2,3} Which is B in our question Hope this helps :) Let me know too if you got it :) </span><span>
</span>Answer: C. {-3.8, 1.2, 3}
The answer is D. dividing both sides by 4 isolates the variable
The Pythagorean theorem applies to the sides of this right triangle.
... x² + (4/7)² = (5/7)²
... x² = 25/49 -16/49
... x = √(9/49)
... x = 3/7
The unknown side has length 3/7.
_____
You might recognize that this is a 3-4-5 right triangle with a scale factor of 1/7.
The expected completion time is μ = 40 weeks.
The random variable, X = 38 weeks (the probable time)
If the standard deviation is σ, then the z-score is z = (x - μ)/σ.
Let us test the given standard deviations.
When σ=1,
z = (38-40)/1 = -2
From standard tables,
P(x<=38) = P(z<=-2) = 0.0228 =2.3%
When σ=2,
z = (38*40)/2 = -1
P(x<=38) = P(z<=-1) = 0.1587 = 15.9%
When σ=4,
z = (38-40)/4 = -0.5
P(x<=38) = P(z<=-0.5) = 0.3085 = 30.9%
Answers:
z=1 => 2.3%
z=2 => 16% (approx)
z=4 => 31% (approx)