A pipe A can fill a cistern in 12 hours, while pipe B can fill it in 8 hours. In how much time will the cistern be filled, if both pipes A and B are opened together?
Given:
Pipe A fills cistern in 12 hours.
Pipe B fills cistern in 8 hours.
Formula Used:
Work rate =
Time
Solution:
Work rate of A = per hour.
Work rate of B = per hour.
Combined work rate =
Time taken together:
T =
Convert 0.8 hours into minutes:
0.8 × 60 = 48 minutes
The cistern will be filled in 4 hours 48 minutes
Alternate method
LCM of 12 and 8 = 24 units
A does 2 units/hour, B does 3 units/hour
Together = 5 units/hour.
Time == 4.8 hours = 4h 48m.
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