$499.96 x .15 = $74.99 off
$499.96 - $74.99 = $451.98
Hope this helps you!
I think it's 9.68 but I might be wrong
Answer:
A sample of 179 is needed.
Step-by-step explanation:
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of
.
That is z with a pvalue of
, so Z = 1.44.
Now, find the margin of error M as such

In which
is the standard deviation of the population and n is the size of the sample.
A previous study found that for an average family the variance is 1.69 gallon?
This means that 
If they are using a 85% level of confidence, how large of a sample is required to estimate the mean usage of water?
A sample of n is needed, and n is found for M = 0.14. So






Rounding up
A sample of 179 is needed.
Correct answer is C.
For example 2, 4, 8, 16, 32...

First no. = x
Second no. = y
Equation Formation
x + y = 6..........equation(i)
x - y = 10...........equation (ii)
x = 6 - y
6 - y - y = 10
6 - 2 y = 10
-2 y = 10 -6
-2 y = 4
y = -2
x = 6 + 2
x = 8
Answer = 8 , -2