Answer:
$616
Step-by-step explanation:
When you add all the values that were added to his account, he added $3,089.When you add all the values that he wrote checks for (subtracted), he took out $2,473. When you subtract 2,473 from 3,089, you get 616, which is how much money is left in his account.
$70 = 270 min
x = 1260 min
Where x is the charge of phone service per 1260 min.
Cross multiply:
1260 * 70 = 270 * x
88200 = 270x
88200/270 = x
x = 326.67
The total charge of cellular phone service for 1260 min is $326.67
Answer:
x=11 degrees
Step-by-step explanation:
45+4x+1=90
46+4x=90
4x=44
x=11
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.
C) X is greater than or equal to 0
(Domain is all the x-values the line goes through)