SOLUTION: one type of air blower can fill a blimp in 6 hours working alone, while a second blower fills the same blimp in 9 hours working alone. how long will it take both blowers working to

Question 275481: one type of air blower can fill a blimp in 6 hours working alone, while a second blower fills the same blimp in 9 hours working alone. how long will it take both blowers working together.I need to know exactly how you got to the conclusion, not just the answer which i know is 3 hours and 36 minutes. Thanks
Found 2 solutions by checkley77, Alan3354:
Answer by checkley77(12844) (Show Source): You can put this solution on YOUR website!
THE FORMULA IS:
1/9+1/6=1/X FIND A COMMON DENOMINATOR & ADD THE LEFT SIDE.
(6+9)/9*6=1/X ADD THE NUMERATOR & MULTIPLY THE DENOMINATOR.
15/54=1/X CROSS MULTIPLY.
15X=54 DIVIDE BY 15.
X=54/15
X=3.6 HOURS TO FILL THE BLIMP WORKING TOGETHER.
PROOF:
1/9+1/6=1/3.6
(6+9)/9*6=1/3.6
15/54=1/3.6
54=15*3.6
54=54

Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
Get it into units that can be added:
One blower does 1/6 of the job per hour.
The other does 1/9 per hour.
Together, they do 1/6 + 1/9 per hour.
1/6 + 1/9 = 15/54 jobs/hour
--> 54/15 hours per job
= 3.6 hours or 3 hr 36 minutes
----------------------
Use the shortcut, product/sum
6*9/(6+9) = 54/15 etc.

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