Aptitude - Pipes & Cisterns Online Quiz

Following quiz provides Multiple Choice Questions (MCQs) related to Pipes & Cisterns. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.

Q 1 - A tap can fill storage in 8 hours and another tap can discharge it in 16 hours. In the event that both the taps are open, the time taken to fill the tank will be:

A - 8 hours

B - 10 hours

C - 16 hours

D - 24 hours

Explanation

```Net part filled in 1 hr = (1/8 ? 1/16)= 1/16
Total time taken to fill the tank = 16 hrs.```

Q 2 - A channels can fill a tank in x hours and another funnel can exhaust it in y (y>x) hours. In the event that both the funnels are open, in how long will the tank be filled?

A - (x-y) hours

B - (y-x) hours

C - xy/(x-y) hours

D - xy/(y-x) hours

Explanation

```Work done by filling pipe in 1 hr = 1/x
Work done by emptying pipe in 1 hr = 1/y
Net filling work done by both in 1 hr = (1/x- 1/y) = (y-x)/xy
∴The tank will be filled in xy/(y-x) hrs.```

Q 3 - A funnel can discharge a tank in 40 minutes. A second pipe with distance across twice as much as that of the first is likewise joined with the tank to purge it. The two together can exhaust the tank in:

A - 8 min

B - 40/3 min

C - 30 min

D - 38 min

Explanation

```A pipe with double diameter will take half time.
So, the second pipe can empty the full tank in 20 min.
Part emptied by both in 1 min. (1/40+ 1/20) = 3/40
Time taken to empty the full tank = 40/3 min.```

Q 4 - Two channels can fill a tank in 15 hours and 12 hours separately and a third pipe can purge it in 4 hours. In the event that the channels are opened all together at 8 am, 9 am and 11am separately, the tank will be exhausted at

A - 11.40 am

B - 12.40 pm

C - 1.40 pm

D - 2.40 pm

Explanation

```Let the tank be emptied in x hrs after 8 am.
Work done by A in x hrs, by B in (x-1) hrs and C in (x-3) hrs = 0
⇒x/15+ (x-1)/12- (x-3)/4 = 0 ⇒ 4x+5(x-1) - 15(x-3) = 0
⇒6x= 40 ⇒x= 20/3 hrs.
⇒x= 6 hrs. 40 min after 8 am
Hence the tank will be emptied at 14 hrs 40 min, i.e., 2:40 pm```

Q 5 - A tank is fitted with two taps A and B. A can fill the tank totally in 45 minutes and B can purge the full tank in 60 minutes. On the off chance that both the taps are opened on the other hand for 1 minute, then in what amount of time the unfilled tank will be filled totally?

A - 2 hrs 55 min

B - 3 hrs 40 min

C - 5 hrs 53 min

D - none of these

Explanation

```Work done by A in 1st minutes and B 2nd minute= (1/45- 1/60)= 1/180
Part filled in 2 min = 1/180
Part filled in 358 min = (1/360*358) =   358/360 = 179/180
Remaining part = (1-179/180) = 1/180
1/45 part is filled by A in (45*1/180) min= 1/4 min.
Total time taken to fill it = 358 1/4 min = 5 hrs.58 min 15 sec.```

Q 6 - A substantial tanker can be filled by two pipes A and B in an hour and 40 minutes separately. How long will it take to fill the tanker from unfilled state if B is utilized for a fraction of the time and A and B fill it together for the other half?

A - 15 min.

B - 20 min.

C - 27.5 min.

D - 30 min.

Explanation

```Let the total time taken be x minute. Then,
(1/40*x/2) + (1/60+ 1/40) x/2= 1 ⇒ x/80 + x/48 = 1
⇒3x+ 5x= 240 ⇒8x= 240 ⇒x= 30
Hence, the required time is 30 minutes.```

Q 7 - A break in the base of a tank can purge the full tank in 6 hours. A channel funnel fills water at the rate of 4 liters for each moment. At the point when the tank is full, the channel is opened and because of the break, the tank is void in 8 hours. The limit of the tank is

A - 5260 ltr.

B - 5760 ltr.

C - 5846 ltr.

D - 6970 ltr.

Explanation

```Part filled in 1 hour = (1/6-1/8)= 1/24
So, the inlet can fill the tank in 24 hours.
Capacity of the tank= volume of water that flows in 24 hrs
= (4*60*24) ltr. = 5760 liters.```

Q 8 - A cistern has 3 pipes A, B and C. A and B can ill it in 3 hours and 4 hours respectively while C can empty the completely filled cistern in 1 hour. If the pipes are opened in order at 3, 4 and 5 pm respectively, at what time will the cistern be empty?

A - 7:12 PM

B - 6:15 PM

C - 8:12 PM

D - 8:35 PM

Explanation

```In 2 hours Pipe A will fill = 2/3 tank
In 1 hour Pipe B will fill = 1/4 tank
Part of tank filled till 5 PM = (2/3) + (1/4)
= 11/12

Remaining part = 1 - (11/12)
= 1/12

Net part emptied when A, b and C are opened = (1/3) +( 1/4) - 1
= (4+3-12)/12
=  -5/12
∴ 5/12 part is emptied in 1 hour.
∴ 11/12 is emptied in (12/5)*(11/12) = 11/5
= 2 hr 12 min
∴ Tank will be emptied at 7:12 PM.```

Q 9 - Two pipes A and B can fill a water tank in 20 and 24 min respectively. A third pipe C can empty at the rate of 3 gallons per minute. If A, B and C opened together fill the tank in 15 min, the capacity of the tank (in gallons) is:

A - 180

B - 150

C - 120

D - 60

Explanation

```Let the capacity of the tank = x gallons
Quantity of the water filled in the tank in 1 min when all the pipes A, B and C are opened simultaneously= x/20 + x/24 - 3
According to question,
x/20 + x/24 - 3 = x/15
or, x/20 + x/24 - x/15 = 3
or, (6x + 5x  - 8x)/120 = 3
or, 3x/120 = 3
or, x = 120 gallons```

Q 10 - Taps A, B and C are connected to a water tank and the rate of flow of water is 42 ltr/hr, 56 ltr/hr and 48 ltr/hr respectively. A and ill fill the tank while tap C empties the tank. If the three taps are opened simultaneously, the tank gets filled up completely in 16 hours. What is the capacity of the tank?

A - 800 ltr

B - 960 ltr

C - 2346 ltr

D - None of these

```Net amount of water filled in 1 hr when all the pipes are opened simultaneously = 42 + 56 ? 48 = 50 ltr