Two pipes A and B can fill up a half full tank in 1.2 hours. The tank was initially empty. Pipe B was kept open for half the time required by pipe A to fill the tank by itself. Then, pipe A was kept open for as much time as was required by pipe B to fill up 1/3 of the tank by itself. It was then found that the tank was 5/6 full. The least time in which any of die pipes can fill the tank fully is

• 1.2(a+b)=1/2
  b/2a +a/3b=5/6
  which gives max value 4 hrs
• 6 years agoHelpfull: Yes(0) No(0)