A tank is fitted with 2 taps , first tap can completly fill the tank
in 45 minutes and second tank can empty the full tank in 1 hour. If both the taps are opened alternatively for one minute, then in how many hours empty tank will be filled completely ?

• Let tank fills in n+1 times and empties n times
  So
  (N+1)*1/45+n*1/60=1
  Gives n=176
  So total time =n+n+1=176+177=353 min.
• 7 years agoHelpfull: Yes(12) No(3)
• 6 hrs.
  
  Part filled in 2 minutes = 1/45 - 1/60 = 1/180
  So time required to fill the tank completely = 2/(1/180) min = 360 min = 6 hrs.
• 7 years agoHelpfull: Yes(7) No(9)
• Part filled in 2 minutes = 1/45 - 1/60 = 1/180
  So time required to fill the tank completely = 2/(1/180) min = 360 min = 6 hrs.
• 7 years agoHelpfull: Yes(2) No(2)
• Answer will be 353mins
• 7 years agoHelpfull: Yes(2) No(2)
• A correct answer is 353min for sure
  Guys who r getting 360 as answer are not doing it in a correct way
• 7 years agoHelpfull: Yes(2) No(3)
• Let the capacity of the tank = X
  Time taken by tap first to fill the tank 45 minutes .
  So tape first takes 45 minutes to fill tank of X litres ,
  Volume of water filled in 1 minute = x / 45 L.
  Tape Second takes 60 minutes to empty the tank of X litres .
  Volume emptied in one Minute = x / 60
  
  Therefore the volume of water filled in opening tap one for a minute then closing it (tap first )and opening of tap second for a minute = x/ 45 - x/ 60
  
  Let the total time taken to fill the tank by alternatively opening and closing of tape first and second tap = t minutes ,
  
  therefore ,
  volume filled in t minutes = capacity of tank
  t (x /45 - x/60) = x
  t (60x - 45x ) / 60*45 = x
  t (15 x ) = 2700 x
  t = 2700 /15
  t= 180 minutes .
  t = 3 hours
• 7 years agoHelpfull: Yes(2) No(2)
• part is filled in 1 minutes is 1/45-1/60= 1/180
  take is filled in alternate minutes i.e in 2 minutes 2/(1/180) i.e 1/360
  we cant consider last 2 minutes because in last minute talk will full . there is no need to empty that
  so we fill 358/360 part and last minute pipe can fill the tank.
  left tank to fill in last minute 1-358/360= 1/180
  first tank can fill in 45 minutes so 45*1/80=1/4 i.e is 15 sec
  total time to fill 358 minutes 15 sec
• 7 years agoHelpfull: Yes(1) No(1)
• 353 minutes.
  
  Solution:-
  In 1 minute part filled by 1 tap = 1/45
  In 1 minute part removed by another tap = 1/60
  
  So 2 min work done by both the taps will be 1/45 - 1/60 = 1/180
  So 1 min work done by both the tap will be 1/360
  
  So for 350 min the work will be 350/360
  
  For 351 min the work will be 350 / 360 + 1/45 = 358/360
  For 352 min the work will be 358/360 - 1/60 = 352/360
  
  For the 353 min the work will be 352/360 + 1/45 = 360/360 = 1
  
  Hence, total time taken to fill the tank completely will be 353 minutes or 5 hours 53 minutes.
• 3 years agoHelpfull: Yes(1) No(0)
• ans : 1.5h
• 7 years agoHelpfull: Yes(0) No(11)
• any one having elitmus questions from pre insta plz send to me at shamashamim8@gmail.com, I would be very grateful.
• 7 years agoHelpfull: Yes(0) No(0)
• 1/45-1/60=1/180
  therefore, it will take 3hrs to fill the tank completely
• 7 years agoHelpfull: Yes(0) No(2)