A) 81 min | B) 108 min |

C) 144 min | D) 192 min |

Explanation:

Let the slower pipe alone fill the tank in x minutes.

Then,faster pipe will fill it in x/3 minutes.

A) 49.5 min | B) 50 min |

C) 51 min | D) 52 min |

Explanation:

The work to be done = Capacity of reservoir = 30 litres.

1^{st} Minute inlet pipe opened 5 lit filled

2^{nd} minute inlet pipe closed; outlet pipe opened 4 lit emptied

In 2 minutes (5 litres - 4 litres = 1lit) is filled into the reservoir.

It takes 2 minutes to fill 1lit it takes 50 minutes to fill 25 litres into the reservoir.

In the 51^{st} minute inlet pipe is opened and the reservoir is filled.

A) 50 m^3/min | B) 60 m^3/min |

C) 72 m^3/min | D) None of these |

Explanation:

Let the filling capacity of the pump be x /min.

Then, emptying capacity of the pump=(x+10) /min.

so,

A) 6 hrs | B) 20/3 hrs |

C) 7 hrs | D) 15/2 hrs |

Explanation:

Now, it is the turn of A and B (3/20) part is filled by A and B in 1 hour.

therefore, Total time taken to fill the tank =(6+1)hrs= 7 hrs

A) 8 | B) 15 |

C) 16 | D) 18 |

Explanation:

Capacity of the tank =(12 x 13.5) liters =162 liters.

Capacity of each bucket =9 liters

Number of buckets needed = 162/9 =18.

A) 6 min.to empty | B) 6 min.to fill |

C) 9 min.to empty | D) 9 min.to fill |

Explanation:

Clearly,pipe B is faster than pipe A and so,the tank will be emptied.

part to be emptied = 2/5

part emptied by (A+B) in 1 minute=

so, the tank will be emptied in 6 min