SOLUTION: one stamping machine can process a batch of labels in 18 minutes. A new model can process a batch in 12 minutes. How long would it take both machines working together to process a 
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Question 591491:  one stamping machine can process a batch of labels in 18 minutes. A new model can process a batch in 12 minutes. How long would it take both machines working together to process a batch of labels? 
 This question is extra credit becaause she has not taught it to us. thanks so much for helping! 
Answer by josmiceli(19441)   (Show Source): You can put this solution on YOUR website!
 Add the rates of processing to get the rate of both together
First machine's rate:
( 1 batch ) / ( 18 min )
Second machine's rate:
( 1 batch ) / ( 12 min )
Let  = minutes to process with both machines
It takes both machines together 7.2 minutes 
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