Home | About Indiatry | Login | Register

    • ( 1 ) Two taps can separately fill a cistern 10 minutes and 15 minutes respectively and when the waste pipe is open, they can together fill it in 18 minutes. The waste pipe can empty the full cistern in?

    • 1) 7 min
    • 2) 13 min
    • 3) 23 min
    • 4) 9 min
    • Discussion in forum
      Answer : 4) 9 min
      Solution : 1/10 + 1/15 - 1/x = 1/18
      x = 9








      discussion


      Answer : 4) 9 min

    • ( 2 ) An electric pump can fill a tank in 3 hours. Because of a leak in the tank, it took 3 ½ hours to fill the tank. The leak can drain out of all the water of the tank in:

    • 1) 21 hrs
    • 2) 25 hrs
    • 3) 12 hrs
    • 4) 24 hrs
    • Discussion in forum
      Answer : 1) 21 hrs
      Solution : Time taken = 3 hours
      Time taken = 3 ½ hours
      Time taken by A and B = 3*(3 1/2)/(3 1/2 -3)
      => (21/2)/((7/2) -3)
      => (21/2)/((7 -6)/2) = 21 hours








      discussion


      Answer : 1) 21 hrs

    • ( 3 ) A cistern has a leak which would empty the cistern in 20 minutes. A tap is turned on which admits 4 liters a minute into the cistern, and it is emptied in 24 minutes. How many liters does the cistern hold?

    • 1) 480 liters
    • 2) 600 liters
    • 3) 720 liters
    • 4) 800 liters
    • Discussion in forum
      Answer : 1) 480 liters
      Solution : Time taken to fill the tank is 1/20
      Time taken to empty the taken is 1/24
      Work done by the inlet in 1 minute = (1/20) -(1/24) = 1/120
      Therefore Volume = 120 X4 liters = 480 liters








      discussion


      Answer : 1) 480 liters

    • ( 4 ) Two pipes X and Y fill a tank in 15 hrs. and 20 hrs. respectively, while a third pipe 'Z' can empty the full tank in 25 hrs. All the three pipes are opened in the beginning. After 10 hrs. Z is closed. In how much time, will the tank be full ?

    • 1) 12 hrs.
    • 2) 13 hrs
    • 3) 16 hrs.
    • 4) 18 hrs
    • Discussion in forum
      Answer : 1) 12 hrs.
      Solution : Part filled in 10 hrs. = 10[(1/15)+(1/20)-(1/25)] = 23/30
      Remaining part = (1- (23/30)) = 7/30
      (x + y )'s 1 hour work = [(1/15) + (1/20)] = 7/60
      7/60 : 7/30 :: 1 : p
      => p=(7/30) * 1 * (60/7) = 2 hrs.
      The tank will be full in (10 + 2) hrs = 12 hrs








      discussion


      Answer : 1) 12 hrs.

    • ( 5 ) A cistern can be filled by pipe A and B in 12 minutes and 10 minutes respectively. The full tank can be emptied by a third pipe C in 8 minutes only. If all the taps be turned on at the same time, the cistern will be full in how much time?

    • 1) 15 1/7 Minutes
    • 2) 17 1/7 Minutes
    • 3) 19 1/7 Minutes
    • 4) 12 1/7 Minutes
    • Discussion in forum
      Answer : 2) 17 1/7 Minutes
      Solution : Pipes A and B can fill a tank in 12 min and 10 min respectively
      =>Part filled by pipe A in minute = 1?12
      and Part filled by pipe B in minute = 1?10
      Pipe C can empty it in 12 minute
      => Part emptied by pipe C in 1 minute = 1?8
      Net part filled by Pipes A,B and C together in 1 minute = (1/12) + (1/10) - (1/8) = 7/120
      i.e, the pipe can be filled in 120/7 = 17 1/7minute








      discussion


      Answer : 2) 17 1/7 Minutes

    • ( 6 ) A leak in the lower portion of a tank can empty the full tank in 9 hrs. An inlet pipe fills water at the rtae of 10 lit. a minute. When the tank is full, the inlet is opened and due to leak, the tank is empty in 16 hrs. How many litres does the cistern hold ?

    • 1) 17,580
    • 2) 17,960
    • 3) 12,342
    • 4) 18,290
    • Discussion in forum
      Answer : 3) 12,342
      Solution : Work done by the inlet in 1 hr = (1/9) - (1/16) = 7/144
      Work done by the inlet in 1 min. = ((7/144) * (1/60)) = 78,640
      Volume of 7/8,640 part = 10 litres.
      Whole volume = 10 * 8,640/7 = 12,342 litres








      discussion


      Answer : 3) 12,342

    • ( 7 ) Two pipes A and B can fill a tank in 9 hours and 3 hours respectively. If they are opened on alternate hours and if pipe A is opened first, how many hours, the tank shall be full?

    • 1) 4 hr
    • 2) 5 hr
    • 3) 2 hr
    • 4) 6 hr
    • Discussion in forum
      Answer : 2) 5 hr
      Solution : Part filled by pipe P in 1 hour = 1/9
      Part filled by pipe Q in 1 hour = 1/3
      Pipe P and Q are opened alternatively.
      Part filled in every 2 hour = (1/9) + (1/3) = (1 + 3)/9 = 4/9
      Part filled in 4 hour = 2 * (4/9) = 8/9
      remaining part =1 - (8/9) = 1/9
      Now it is pipe P's turn.
      Time taken by pipe P to fill the remaining 1/9 part = (1/9)/(1/9) = 1 hour
      Total time taken = 4 hour + 1 hour = 5 hour








      discussion


      Answer : 2) 5 hr

    • ( 8 ) Two pipes A and B can fill a tank in 50 minutes and 60 minutes respectively. If both thepipes open together for 10 minutes, then A is closed. In how much time A fill the remaining tank?

    • 1) 38 Minutes
    • 2) 40 Minutes
    • 3) 33 Minutes
    • 4) 36 Minutes
    • Discussion in forum
      Answer : 1) 38 Minutes
      Solution : Part filled by pipe A in 1 minute = 1/50
      Part filled by pipe B in 1 minute = 1/60
      Part filled by pipe A and pipe B in 1 minute = (1/50) + (1/60) = 11/300
      Pipe A and pipe B were open for 10 minutes
      Part filled by pipe A and pipe B in 10 minutes = 10 * 11/300 = 11/30
      Remaining part = 1 - (11/30) = 19/30
      Time taken by pipe B to fill this remaining part = (19/30)/(1/60) = 38 minutes








      discussion


      Answer : 1) 38 Minutes

    • ( 9 ) Pipe A can fill a tank in 8 hours, pipe B in 6 hours and pipe C in 24 hours. If all the pipes are open, in how many hours will the tank be filled?

    • 1) 2.4 hrs
    • 2) 3 hrs
    • 3) 4 hrs
    • 4) 4.2 hrs
    • Discussion in forum
      Answer : 1) 2.4 hrs
      Solution : Part filled by pipe A in 1 minute = 1/8
      Part filled by pipe B in 1 minute = 1/6
      Part filled by pipe C in 1 minute = 1/12
      Net part filled by (A+B+C ) in 1 minute = (1/8) + (1/6) + (1/12) = (3 + 4 + 2)/24 = 9/24 = 3/8
      A, B and C pipes can fill the tank in 2.4 hr








      discussion


      Answer : 1) 2.4 hrs

    • ( 10 ) Two pipes A and B can fill a tank is 8 minutes and 14 minutes respectively. If both the taps are opened simultaneously, and the tap A is closed after 3 minutes, then how much more time will it take to fill the tank by tap B?

    • 1) 6 min 15sec
    • 2) 5 min 45 sec
    • 3) 5 min 15 sec
    • 4) 6 min 30 sec
    • Discussion in forum
      Answer : 2) 5 min 45 sec
      Solution : Part filled by pipe A in 1 minute = 1/8
      Part filled by pipe B in 1 minute = 1/14
      Part filled by pipe A and pipe B in 1 minute = (1/8) + (1/14) = 11/56
      Pipe A and pipe B were open for 3 minutes
      Part filled by pipe A and pipe B in 3 minutes = 3 * 11/56 = 33/56
      Remaining part = 1 - (33/56) = 23/56
      Time taken by pipe B to fill this remaining part = (23/56)/(1/14) = 23/4 minutes = 5 3/4 minutes = 5 min 45 sec








      discussion


      Answer : 2) 5 min 45 sec





Top