Answer:
2.0
Step-by-step explanation:
Couldn't really understnd what you wrote but I'll assume it's the standard deviation of a fair, 7-sided die
The standard deviation is just the square root of the variance (which is just the second moment minus the first moment squared)
The first moment (AKA the average is..)

The second moment is..


Answer:
I believe this is how you do it
Step-by-step explanation:
csc∅tan∅
(1/sin∅)(sin∅/cos∅)
(sin∅)/(sin∅cos∅)
1/(cos∅)
sec∅
csc²∅tan²∅sin∅
1/(sin²∅) * tan²∅ * sin∅
tan²∅/sin²∅ * sin∅
tan²∅/sin∅
By definition we have the following equation:
t = d / v
Where,
t: time
d: distance
v: speed
For this case we have:
d / 30 + d / 4 = 17
Rewriting we have:
2d + 15d = 17 (60)
17d = 17 (60)
d = 60 mi
Then, the walking time is
t = d / v
t = 60/4
t = 15 hours
Answer:
She walked
t = 15 hours