$25. 25 x 3 is 75. Plus the 100 is 175. 200 - 175 is $25
Answer:
a) The confidence interval is
.
Step-by-step explanation:
We have to calculate a confidence interval (CI) of a difference of proportions.
For the existing procedure, the proportion is:

For the new procedure, the proportion is:

To calculate the CI, we need to estimate the standard deviation

For a 90% CI, the z-value is 1.64.
Then, the CI is:

The equation that models the total cost is y = 100 + 22.5m
Step-by-step explanation:
Fitness member ship cost = $100
Monthly fee = $25
Discount = 10% on monthly fee
To calculate new monthly fee after discount,
25 - (25*10%) --> 25 - 2.5 --> $22.5
Number of months = m
Fee in m months = 22.5*m = 22.5m
<u>Equation:</u>
(c) is constant which is the membership fee
(x) is the monthly fee $22.5
(m) is the number of months
(y) is the total cost
So,
y = mx + c
y = m(22.5) + 100
y = 100 + 22.5m
Therefore, the equation that models the total cost is y = 100 + 22.5m
Keyword: Equation
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Divide 84.87 by 1.15, and you get 73.8
Then you can check your work by multiplying 73.8 by 1.15 and you get 84.87