PIPE AND CISTERN MCQ SET 3
1. An inlet pipe can fill an empty tank in 4 1/2 hours while an outlet pipe drains a completely filled tank in 7 1/5 hours . The tank is initially empty , and the two pipes are alternately opened for an hour each , till the tank is completely filled , starting with the inlet pipe . In how many hours will the tank be completely filled?
(a) 24
(b) 20 1/4
(c) 20 3/4
(d) 22 3/8
Answer: C
2. A monkey climbs a pole 100 meters high . In the first minute , it climbs 6 meters , and in the second minute , it slips down 4 meters . How much time will the monkey take to reach the top ?
(a) 90 min
(b) 95 min
(c) 100 min
(d) 120 min
Answer: B
3. A monkey climbs a 60 m high pole . In first minute he climbs 6m and slips down 3 m in the next minute . How much time is required by it to reach the top?
(a) 35 min
(b) 37 min
(c) 33 min
(d) 40 min
Answer: B
4. A drunkard walks 5 steps forward in a narrow lane and comes back 3 steps , then again takes 5 steps forward and comes back 3 steps , and so on . Each of his steps is 1 meter long and takes 1 second . There is a pit at a distance of 11 meters from the starting point in the lane . After how many seconds will the drunkard fall into this pit ?
(a) 21 sec .
(b) 29 sec.
(c) 31 sec.
(d) 37 sec.
Answer: B
5. Three pipes A , B and C are connected to a tank . A and B can fill it in 20 and 30 minutes respectively while C can empty it in 15 minutes . If all three are opened one by one for 1 minute each , find the time taken to fill the tank .
(a) 167 min
(b) 160 min
(c) 165 min
(d) None of these
Answer: A
6. A tank when full can be emptied by an outlet pipe A in 5.6 hours , while an inlet pipe B can fill the same empty tank in 7 hours . If pipes A and B are turned on alternatively for 1 hour each starting with pipe A when the tank is full , how long will it take to empty the tank?
(a) 48 hours
(b) 47 hours
(c) 56 hours
(d) 55 hours
Answer: B
7. Two pipes P and Q can fill a tank in 15 minutes and 45 minutes respectively . Pipe R can empty the tank in 30 minutes . If pipe P is kept open for one minute , then pipe Q for one minute , and then pipe R for one minute , and this process is repeated until the tank is filled , how much time will it take to fill the tank?
(a) 51 5/6 minute
(b) 18 minute
(c) 54 minute
(d) 51 4/5 minute
ย Answer: A
8. A tank has three pipes P , Q and R . Only P can fill it in 5 hours and only Q can fill it in 6 hours . If the tank is full then R can empty it in 10 hours . These pipes are opened at 6 am , 7 am and 8 am respectively . In this sequence every pipe is opened for one hour in turn . At what time will the tank be full ?
(a) 4:30 pm
(b) 3:30 pm
(c) 4 pm
(d) 3 pm
Answer: C
9. Pipes x and y alone can completely fill a tank in 30 hours and 45 hours respectively . If pipes x and y are opened alternately with z for one hour , the tank is 70% filled in 15 hours . What is the time taken by pipe z to complete fill the tank , if its capacity is increased by 50%?
(a) 40 hours
(b) 45 hours
(c) 36 hours
(d) 50 hours
Answer: C
10. A tank is filled through three pipes x , y and x . Pipe x and y clone can fill the tank in 30 hours and 45 hours , respectively . In the first hour , pipes x and z fill the tank , and in the second half , pipes y and z fill the tank , and this process continues in this way , filling 70% of the tank in 15 hours . If pipe z , when opened along with pipes x and y provides 75% of the original supply , how much time will pipe z take to fill the tank by itself ?
(a) 40.5 hours
(b) 56.25 hours
(c) 54 hours
(d) 45 hours
Answer: A
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