69 is the median in this set
Answer:
Step-by-step explanation:
Given that Darcie wants to donate minimum 3 blankets to donate to a homeless shelter. No of days left =60
No of days to complete one blanket = 1/(1/15) = 15 days
Hence in 60 days she has to complete ≥3 blankets
No of days she has to utilize for this will be ≥3(15)=45
No of days she can skip crocheting ≤15
Let x be the no of days crocheted and y no of days skipped
Then x+y≤60
See the graph attached as x axis for days crocheted and y for days skipped
No of blankets can be either 3 or 4.
Notice that

so the constraint is a set of two lines,

and only the first line passes through the first quadrant.
The distance between any point
in the plane is
, but we know that
and
share the same critical points, so we need only worry about minimizing
. The Lagrangian for this problem is then

with partial derivatives (set equal to 0)



We have

which tells us that

so that
is a critical point. The Hessian for the target function
is

which is positive definite for all
, so the critical point is the site of a minimum. The minimum distance itself (which we don't seem to care about for this problem, but we might as well state it) is
.
Answer:
The standard deviation of car age is 2.17 years.
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 7.5
(a) If 99.7% of the ages are between 1 year and 14 years, what is the standard deviation of car age?
This means that 1 is 3 standard deviations below the mean and 14 is 3 standard deviations above the mean.
So

I want to find 



The standard deviation of car age is 2.17 years.