Answer:
8.885
Step-by-step explanation:
Given that :
Sample size, n = 10
The average range, Rbar for all samples = 5
The upper control limit, UCL for the R-chart is :
UCL L= D4Rbar 
From the control chart constant table, D4 = 1.777
Hence, 
UCL = 1.777 * 5
UCL = 8.885
The UCL for the R-chart is 8.885
 
        
             
        
        
        
I think the answer is negative 8 square root 726 
then the answer if I am right sorry if I am not would be negative 88 square root 6
again sorry if wrong
        
             
        
        
        
The average of both sides are the same.
Hope I helped! ( Smiles )