Answer:
75cm^2
Step-by-step explanation:
When you say a rectangular prism, it means it has the base has 4 sides of which opposite sides are equal as a rectangle. This sides substends so we have a total of 6 surfaces in this prism.
This 6 surfaces has 3 surface area the same.
The surface area = sum of area of all faces.
325= 50 + 50 + 37.5 + 37.5 + 2x; where X is the area of the surface unknown.
325= 100+ 75 + 2x
325-175= 150
150= 2x
X= 150/ 2 = 75 cm^2
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.