Answer: 50
Step-by-step explanation: 12 1/2 times 4 is 50
 
        
             
        
        
        
You can find a common demominator and then change 8 1/4 into a mixed number and just subtract
        
             
        
        
        
Answer:
40 minutes
Step-by-step explanation:
12 envelopes every 10 minutes.
48 envelopes = 40 minutes