SOLUTION: Crew A can clean the Megadome in eight hours and Crew B can clean it in twelve hours. After a night game, crew A began a cleanup at midnight and was joined by crew B at 2:00 A.M. W

Question 370506: Crew A can clean the Megadome in eight hours and Crew B can clean it in twelve hours. After a night game, crew A began a cleanup at midnight and was joined by crew B at 2:00 A.M. When was the job completed?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Crew A can clean the Megadome in eight hours and Crew B can clean it in twelve hours. --------------------------
A rate = 1/8 job/hr
B rate = 1/12 job/hr
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After a night game, crew A began a cleanup at midnight and was joined by crew B at 2:00 A.M. When was the job completed?
---------------------------------------------------
Let "x" be the number of hours they worked together
----
Equation:
work done + work done = job done
----
2(1/8) + (1/8 + 1/12)x = 1 job
----
1/4 + (20/(8*12))x = 1
---
1/4 + (5/24)x = 1
-----
(5/24)x = 3/4
---
x = (3/4)(24/5)
---
x = 18/5 hrs.
----
x = 3.6 hrs
---
x = 3hr 36 minutes
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Hour Answer: Job completed at 5:36 AM
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Cheers,
Stan H.

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