Question

Two pipes P and Q can fill a cistern in 3 and 6 min
respectively, while an empty pipe R can empty the
cistern in 4 min. All the three pipes are opened
together and after 2 min pipe R is closed. Find when
the tank will be full.
[Dec 2010]
(a) 3 min
(b) 6 min
(c) 5 min
(d) 8 min
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Answer 1

Answer:

option [d] 8min

Step-by-step explanation:

sorry if u are not agreed with my ans or if its wrong

because i am newly joined the brainly platform.............:[

Answer 2

Answer:

3 mjn

Step-by-step explanation:

quantity fill in 1 min if all three pipes are open =1/3+1/6-1/4

=(4+2-3)/12 taking lcm of denominator

3/12=1/4

so,if all pipes are opens for 2 min

so part which has to be filled is 2*1/4=1/2

now only pipe P and Q are open so P and Q fill the tank in one minute =1/3+1/6=1/2

IN first two min 1/2 tank already filled and after that R is close so only one minute is necessary for fill the remaining half tank

so total time 2min+1min=3 min