PR must be less than 26cm as PQ + QR = 26cm
PR must be more than 16cm as PD- QR = 16cm
At both those limits the sides would lay on top of each other.
        
                    
             
        
        
        
The answer is D: -1
If you plug it in, it’s the only one that works
        
                    
             
        
        
        
Ok so you could use the equation h=t divided by w. 
h represents the hours volunteered in one week. 
t represents the amount of hours volunteered in the original amount of weeks. 
w represents the original amount of weeks. 
When you plug In the numbers you get h=72 divided by 12 which gives you h=6 so Penn volunteered 6 hours in one week. 
You know the answer is reasonable because there are 168 hours in a week, so Penn could easily spend 6 hours a week volunteering. 
Sorry if my explanation is confusing, but I tried to help. Good luck :)
        
             
        
        
        

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I believe the answer is "true".