Using the distributive property, 10x + 20.
(5 * 4) + (5 * 2x) = 20 + 10x = 10x + 20.
        
                    
             
        
        
        
Answer:
Yes, there is evidence to support that claim that instructor 1 is more effective than instructor 2
Step-by-step explanation:
We can conduct a hypothesis test for the difference of 2 proportions.  If there is no difference in instructor quality, then the difference in proportions will be zero.  That makes the null hypothesis
H0:  p1 - p2 = 0
The question is asking whether instructor 1 is more effective, so if he is, his proportion will be larger than instructor 2, so the difference would result in a positive number.  This makes the alternate hypothesis
Ha:  p1 - p2 > 0
This is a right tailed test (the > or < sign always point to the critical region like an arrowhead)
We will use a significance level of 95% to conduct our test.  This makes the critical values for our test statistic: z > 1.645.  
If our test statistic falls in this region, we will reject the null hypothesis.
<u>See the attached photo for the hypothesis test and conclusion</u>
 
        
             
        
        
        
To find a number in between you could multiply 39/130 by 2/2
and 40/130 by 2/2 to get
78/260 and 80/260
        
             
        
        
        
The answer to the problem is D
        
                    
             
        
        
        
Her chances of getting that should be 2/6