SOLUTION: Problem: Manuel arranges all the seats in the auditoriums in 7 hours, while Pedro takes only 5 hours. How long will it take if they work together? I need your help about this, b

Question 123887: Problem: Manuel arranges all the seats in the auditoriums in 7 hours, while Pedro takes only 5 hours. How long will it take if they work together?
I need your help about this, becuase this is our assignment.
thank you
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Manuel arranges all the seats in the auditoriums in 7 hours, while Pedro takes only 5 hours. How long will it take if they work together?
:
Let t = time required, when they work together
:
Let the completed job = 1
:
A simple equation
M's fraction of the job + P's fraction of the job = 1 (completed job)
:
+ = 1
:
Multiply equation by a multiple of 5 and 7 to get rid of the denominators (35)
35* + 35* = 35(1)
cancel out the denominators and you have:
:
5t + 7t = 35
:
12t = 35
:
t =
t = 2.917 hrs working together
;
:
Check our solution:
+ = 1
.4167 + .5834 = 1.000; confirms our solution
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