Answer:
D and E because they are bigger than 28. C is 28 but there isn't a greater OR EQUAL sign next to it
Answer: 37
Step-by-step explanation:
Given : Significance level : 
Critical value : 
margin of error : E= 1 mile per gallon
Population standard deviation:
miles per gallon.
We know that when the population standard deviation is known then the formula to find the sample size is given by :

[Round to the next whole number.]
Hence, the required number of automobiles should be used in the test = 37
substitution and elimination means that you need to use one equation and substitute it in place of some variable in the other equation.
Consider the above two equations.
Take equation 1, which is 4x-2y=22 => x=(22+2y)/4
substitute the x value gained above in equation 2.
so, 2((22+2y)/4)+4y=6
22+2y+8y=12 => 10y = -10 => y= -1.
Substitute y= -1 in x value obtained in the beginning.
So, x= (22 - 2)/4 => 5.
There fore, x= 5 and y= -1
Hope it helps.
Answer:
The answer to the first question is 7.15
The answer to the second question is 1.73