Let

denote the number of minutes spent brushing his teeth, and let

be the mean and

the standard deviation for this distribution.

The z-score corresponding to this probability is approximately

, which means

Next, (note the sign change)

The corresponding z-score is approximately

, so you have

Solving the two equations for

and

, you'll find that the mean is approximately

and the standard deviation is approximately

.
Answer:
x=−7.974656,0.038604
Step-by-step explanation:
4x4+13x3−124x2+212x−8=0
Brainleist please
Answer:
Franklin sold 5x bars.
Step-by-step explanation:
Franklin Sells 5x bars. I assume the question is asking for an expression with the usage of X instead of an actual value or when that is attainable. If there's any more information that you can provide, let me know and I'll redo the problem.
Answer:
roughly 12.56 units
Step-by-step explanation:
Since the perimeter of a circle is 2*pi*r, we can divide it by two or multiply by half in order to find the perimeter of a semicircle
half of the diameter is the radius, so 8/2 =4, r=4
Plug in what we know...
C=2*pi*4
Solve
2*3.14*4
25.12
divide by 2
25.12/2=12.56
12.56 units is the perimeter