Answer: The sample size would be needed = 385
Step-by-step explanation:
Let p be the prior population proportion.
Margin of error = E
When not estimate of p is given , the formula to calculate the minimum sample size <em>n</em> =  , where z* = critical value for given confidence interval.
 , where z* = critical value for given confidence interval.
Here z* for 95% confidence level is 1.96.
E=5%=0.05
Then 
Hence, the sample size would be needed = 385
 
        
             
        
        
        
The linear combination method is the same as the elimination method.  Let's multiply the second equation by -2 so the x terms cancel each other out. When we do that we get a system of 

 and 

.  The x-terms cancel each other out giving us 

 and y = -3.  Now sub -3 into one of the equations to solve for x.  x+2(-3)=-4, and x - 6 = -4.  x = 2.  So the solution for our system is (2, -3)
 
        
        
        
5.692 is a terminating decimal because the decimal stopped at the digit of 2.
Hope this helps!