SOLUTION: Crew No. 1 can finish installation of an antenna tower in 200 man-hour while Crew No. 2 can finish the same job in 300 man-hour. How long will it take both of the crews to finish t

Question 658838: Crew No. 1 can finish installation of an antenna tower in 200 man-hour while Crew No. 2 can finish the same job in 300 man-hour. How long will it take both of the crews to finish the same job, working together?
Answer by checkley79(3341) (Show Source): You can put this solution on YOUR website!
1/200+1/300=1/X
FIND A COMMON DENOMINATOR FOR THE 2 FRACTIONS.
200 400 600 800
300 600 900 600 LOOKS LIKE A SOLUTION.
(3*1+2*1)/600=1/X
(3+2)/600=1/X
5/600=1/X
5X=600
X=600/5
X=120 HOURS ANS.

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