Two pipes A and B can fill a tank in 15 minutes and 20 minutes respectively. Both the pipes are opened together but after 4 minutes, pipe A is turned off. What is the total time required to fill the tank? (a). 10 min 20 sec (b). 11 min 45 sec (c). 12 min 30 sec (d). 14 min 40 sec
By BYJU'S Exam Prep
Updated on: September 25th, 2023
It is given that
Time is taken to fill a tank by pipe A = 15 minutes
Time is taken to fill a tank by pipe B = 20 minutes
Both pipes are opened together
Time at which pipe A is turned off = 4 minutes
So the part filled in 4 minutes = 4 (1/15 + 1/20)
By further calculation
= 7/15
The remaining part will be = 1 – 7/15 = 8/15
Part filled by B in 1 minute = 1/20
The ratio will be
1/20: 8/15:: 1: x
We get
x = (8/15 x 1 x 20) = 10 ⅔ min = 10 minutes 40 seconds
Total time required to fill the tank = 4 minutes + 10 minutes + 40 seconds = 14 minutes 40 seconds
Therefore, the total time required to fill the tank is 14 minutes and 40 seconds.
Summary:
Two pipes A and B can fill a tank in 15 minutes and 20 minutes respectively. Both the pipes are opened together but after 4 minutes, pipe A is turned off. What is the total time required to fill the tank? (a). 10 min 20 sec (b). 11 min 45 sec (c). 12 min 30 sec (d). 14 min 40 sec
Two pipes A and B can fill a tank in 15 minutes and 20 minutes respectively. Both the pipes are opened together but after 4 minutes, pipe A is turned off. The total time required to fill the tank is 14 minutes and 40 seconds.
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