Aptitude Pipes and Cisterns Test Paper 2


6) A cistern can be filled by an inlet in 6 hours and can be emptied by an outlet in 8 hours. If the inlet and outlet are opened together, in what time the cistern can be filled?

  1. 24 hours
  2. 26 hours
  3. 20 hours
  4. 18 hours

Correct Option (A)

Answer with explanation:

Part of the tank filled by the inlet in one hour = Apti Pipes and Cisterns
Part of the tank emptied by the outlet in one hour = Apti Pipes and Cisterns
Net part of the tank filled in one hour = Apti Pipes and Cisterns - Apti Pipes and Cisterns

Apti Pipes and Cisterns

Apti Pipes and Cisterns part of the tank is filled in one hour

∴ The whole tank will be filled in 24 hours.

Solution 2:
Apply formula; =Apti Pipes and Cisterns

X = 6 hours

Y = 8 hours
∴ Required time = Apti Pipes and Cisterns = 24 hours


7) 20 buckets can fill a tank when the capacity of each bucket is 12 liters. If the capacity of each bucket is 10 liters, find the number of buckets required to fill the tank.

  1. 30 buckets
  2. 34 buckets
  3. 24 buckets
  4. 27 buckets

Correct answer; option (C)

Answer with explanation:

Capacity of each bucket = 12 liters

20 buckets can fill the tank. So, capacity of tank = 20 * 12= 240 liters

New capacity of bucket = 10 liters

So, 10 liters can be poured into the tank by one bucket

Apti Pipes and cisterns50

8) Two pipes working together can fill a fish tank in 12 minutes. If one pipe fills the fish tank 10 minutes faster than the second pipe, in what time the second pipe alone can fill the fish tank?

  1. 20 minutes
  2. 25 minutes
  3. 30 minutes
  4. 35 minutes

Correct answer; option (C)

Answer with explanation:

Let the first pipe fill the reservoir in X minutes

So, the second pipe will fill the reservoir in (X+10) minutes

As per question;

Apti Pipes and cisterns51

12X +120 + 12X = X2 + 10X

X2 +10X 24X -120 = 0

X2 14X -120 =0

X2 - 20X+6X 120=0

X(X-20) +6(X-20) =0

(X+6) (X-20) = 0

X = 20

∴Second pipe will fill the reservoir in 20 + 10= 30 minutes


9) 25 outlets working 6 hours a day, can empty a reservoir in 10 days. If only 15 outlets are operational and work for 4 hours a day, in how many days the reservoir can be emptied?

  1. 20 days
  2. 18 days
  3. 22 days
  4. 25 days

Correct answer; option (D)

Answer with explanation:

Apply formula used in work and time problems; M1D1T1W2 = M2D2T2W1

M1= 25 outlets, D1=10 days, T1= 6 hours/day, W2 = to fill the reservoir

M2= 15 outlets, D2=? T2 = 4 hours/day, W1= to fill the reservoir

W1=W2

So we have; M1D1T1= M2D2T2

25*10*6=15*D2*4

1500 = 60 * D2

Apti Pipes and cisterns52

10) Pipe A can fill a tank in 12 minutes whereas pipe A along with pipe B can fill the same tank in 8 minutes. In what time pipe B alone can fill the tank?

  1. 24 minutes
  2. 20 minutes
  3. 25 minutes
  4. 22 minutes

Correct answer; option (A)

Answer with explanation:

Part of the tank filled by pipe A in one minute=Apti Pipes and cisterns53

Part of the tank filled by A+B in one minute =Apti Pipes and cisterns54

Part of the tank filled by B alone =Apti Pipes and cisterns55

Apti Pipes and cisterns56

∴ Pipe B will fill the whole tank in 24 minutes.

Solution 2:

Apti Pipes and cisterns57

X= 12 minutes

Y=?

As per question;

Apti Pipes and cisterns58

12Y= 8Y+96

4Y= 96

Y = 24 minutes


Aptitude Pipes and Cisterns Test Paper 1
Aptitude Pipes and Cisterns Test Paper 3
Pipes and Cisterns Concepts





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