Answer:
D
Step-by-step explanation:
 
5x-2+2x+1
5x+2x+1-2
7x-1
 
        
             
        
        
        
Answer:
A sample of 18 is required.
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:
 level, that is the subtraction of 1 by the confidence interval divided by 2. So:
 
Now, we have to find z in the Z-table as such z has a p-value of  .
.
That is z with a pvalue of  , so Z = 1.88.
, so Z = 1.88.
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.
 is the standard deviation of the population and n is the size of the sample.
A previous study indicated that the standard deviation was 2.2 days.
This means that 
How large a sample must be selected if the company wants to be 92% confident that the true mean differs from the sample mean by no more than 1 day?
This is n for which M = 1. So
 
 



Rounding up:
A sample of 18 is required.
 
        
             
        
        
        
If you're on about us tons then it = 20 
However if it's tonnes then it = 18.143695 
        
             
        
        
        
The answer is x=34 degrees.