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.
Answer:
x = 9.17 (nearest hundredth)
The variable x is the amount the student needs to save each month in addition to his usual saved amount of $20.
Step-by-step explanation:
350 = 12(x + 20)
Multiply out brackets: 350 = 12x + 240
Subtract 240 from both sides: 110 = 12x
Divide both sides by 12: 9 1/6 = x
x = 9.17 (nearest hundredth)
The variable x is the amount the student needs to save each month in addition to his usual saved amount of $20.
Commutative property.
Mark brainliest
2250
50*(2+100)/2
50*102/2
50*51
2250
When ANY number is multiplied by its own reciprocal, the product is ' 1 '.
