SOLUTION: Computer A takes 3 minutes to process an input while computer B takes 4 minutes. If computers A , B and C can process an average of 15 inputs in one hour. How many minutes does com

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Computer A takes 3 minutes to process an input while computer B takes 4 minutes. If computers A , B and C can process an average of 15 inputs in one hour. How many minutes does com      Log On


   

Question 884800: Computer A takes 3 minutes to process an input while computer B takes 4 minutes. If computers A , B and C can process an average of 15 inputs in one hour. How many minutes does computer C alone take to process one input?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Computer A takes 3 minutes to process an input while computer B takes 4 minutes.
If computers A , B and C can process an average of 15 inputs in one hour.
How many minutes does computer C alone take to process one input?
:
Maybe we can coin a phrase, "input-minutes"
therefore
15 inputs in 60 min = 900 input-minutes
Let c = no. of min per input for C computer
:
A shared work equation
A + B + C = 900
all working for 60 min
3(60) + 4(60 + 60c = 900
180 + 240 + 60c = 900
420 + 60c = 900
60c = 900 - 420
60c = 480
c = 480/60
c = 8 min per input for C
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Did we make sense here?